355 lines
13 KiB
C
355 lines
13 KiB
C
/*******************************************************************************************
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*
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* raylib [shapes] example - top down lights
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*
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* Example originally created with raylib 4.2, last time updated with raylib 4.2
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*
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* Example contributed by Vlad Adrian (@demizdor) and reviewed by Ramon Santamaria (@raysan5)
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*
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* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
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* BSD-like license that allows static linking with closed source software
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*
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* Copyright (c) 2022-2023 Jeffery Myers (@JeffM2501)
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*
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********************************************************************************************/
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#include "raylib.h"
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#include "raymath.h"
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#include "rlgl.h"
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// Custom Blend Modes
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#define RLGL_SRC_ALPHA 0x0302
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#define RLGL_MIN 0x8007
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#define RLGL_MAX 0x8008
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#define MAX_BOXES 20
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#define MAX_SHADOWS MAX_BOXES*3 // MAX_BOXES *3. Each box can cast up to two shadow volumes for the edges it is away from, and one for the box itself
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#define MAX_LIGHTS 16
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// Shadow geometry type
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typedef struct ShadowGeometry {
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Vector2 vertices[4];
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} ShadowGeometry;
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// Light info type
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typedef struct LightInfo {
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bool active; // Is this light slot active?
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bool dirty; // Does this light need to be updated?
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bool valid; // Is this light in a valid position?
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Vector2 position; // Light position
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RenderTexture mask; // Alpha mask for the light
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float outerRadius; // The distance the light touches
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Rectangle bounds; // A cached rectangle of the light bounds to help with culling
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ShadowGeometry shadows[MAX_SHADOWS];
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int shadowCount;
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} LightInfo;
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LightInfo lights[MAX_LIGHTS] = { 0 };
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// Move a light and mark it as dirty so that we update it's mask next frame
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void MoveLight(int slot, float x, float y)
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{
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lights[slot].dirty = true;
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lights[slot].position.x = x;
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lights[slot].position.y = y;
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// update the cached bounds
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lights[slot].bounds.x = x - lights[slot].outerRadius;
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lights[slot].bounds.y = y - lights[slot].outerRadius;
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}
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// Compute a shadow volume for the edge
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// It takes the edge and projects it back by the light radius and turns it into a quad
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void ComputeShadowVolumeForEdge(int slot, Vector2 sp, Vector2 ep)
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{
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if (lights[slot].shadowCount >= MAX_SHADOWS) return;
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float extension = lights[slot].outerRadius*2;
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Vector2 spVector = Vector2Normalize(Vector2Subtract(sp, lights[slot].position));
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Vector2 spProjection = Vector2Add(sp, Vector2Scale(spVector, extension));
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Vector2 epVector = Vector2Normalize(Vector2Subtract(ep, lights[slot].position));
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Vector2 epProjection = Vector2Add(ep, Vector2Scale(epVector, extension));
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lights[slot].shadows[lights[slot].shadowCount].vertices[0] = sp;
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lights[slot].shadows[lights[slot].shadowCount].vertices[1] = ep;
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lights[slot].shadows[lights[slot].shadowCount].vertices[2] = epProjection;
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lights[slot].shadows[lights[slot].shadowCount].vertices[3] = spProjection;
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lights[slot].shadowCount++;
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}
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// Draw the light and shadows to the mask for a light
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void DrawLightMask(int slot)
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{
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// Use the light mask
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BeginTextureMode(lights[slot].mask);
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ClearBackground(WHITE);
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// Force the blend mode to only set the alpha of the destination
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rlSetBlendFactors(RLGL_SRC_ALPHA, RLGL_SRC_ALPHA, RLGL_MIN);
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rlSetBlendMode(BLEND_CUSTOM);
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// If we are valid, then draw the light radius to the alpha mask
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if (lights[slot].valid) DrawCircleGradient((int)lights[slot].position.x, (int)lights[slot].position.y, lights[slot].outerRadius, ColorAlpha(WHITE, 0), WHITE);
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rlDrawRenderBatchActive();
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// Cut out the shadows from the light radius by forcing the alpha to maximum
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rlSetBlendMode(BLEND_ALPHA);
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rlSetBlendFactors(RLGL_SRC_ALPHA, RLGL_SRC_ALPHA, RLGL_MAX);
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rlSetBlendMode(BLEND_CUSTOM);
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// Draw the shadows to the alpha mask
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for (int i = 0; i < lights[slot].shadowCount; i++)
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{
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DrawTriangleFan(lights[slot].shadows[i].vertices, 4, WHITE);
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}
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rlDrawRenderBatchActive();
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// Go back to normal blend mode
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rlSetBlendMode(BLEND_ALPHA);
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EndTextureMode();
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}
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// Setup a light
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void SetupLight(int slot, float x, float y, float radius)
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{
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lights[slot].active = true;
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lights[slot].valid = false; // The light must prove it is valid
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lights[slot].mask = LoadRenderTexture(GetScreenWidth(), GetScreenHeight());
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lights[slot].outerRadius = radius;
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lights[slot].bounds.width = radius * 2;
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lights[slot].bounds.height = radius * 2;
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MoveLight(slot, x, y);
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// Force the render texture to have something in it
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DrawLightMask(slot);
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}
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// See if a light needs to update it's mask
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bool UpdateLight(int slot, Rectangle* boxes, int count)
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{
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if (!lights[slot].active || !lights[slot].dirty) return false;
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lights[slot].dirty = false;
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lights[slot].shadowCount = 0;
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lights[slot].valid = false;
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for (int i = 0; i < count; i++)
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{
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// Are we in a box? if so we are not valid
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if (CheckCollisionPointRec(lights[slot].position, boxes[i])) return false;
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// If this box is outside our bounds, we can skip it
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if (!CheckCollisionRecs(lights[slot].bounds, boxes[i])) continue;
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// Check the edges that are on the same side we are, and cast shadow volumes out from them
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// Top
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Vector2 sp = (Vector2){ boxes[i].x, boxes[i].y };
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Vector2 ep = (Vector2){ boxes[i].x + boxes[i].width, boxes[i].y };
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if (lights[slot].position.y > ep.y) ComputeShadowVolumeForEdge(slot, sp, ep);
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// Right
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sp = ep;
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ep.y += boxes[i].height;
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if (lights[slot].position.x < ep.x) ComputeShadowVolumeForEdge(slot, sp, ep);
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// Bottom
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sp = ep;
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ep.x -= boxes[i].width;
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if (lights[slot].position.y < ep.y) ComputeShadowVolumeForEdge(slot, sp, ep);
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// Left
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sp = ep;
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ep.y -= boxes[i].height;
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if (lights[slot].position.x > ep.x) ComputeShadowVolumeForEdge(slot, sp, ep);
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// The box itself
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lights[slot].shadows[lights[slot].shadowCount].vertices[0] = (Vector2){ boxes[i].x, boxes[i].y };
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lights[slot].shadows[lights[slot].shadowCount].vertices[1] = (Vector2){ boxes[i].x, boxes[i].y + boxes[i].height };
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lights[slot].shadows[lights[slot].shadowCount].vertices[2] = (Vector2){ boxes[i].x + boxes[i].width, boxes[i].y + boxes[i].height };
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lights[slot].shadows[lights[slot].shadowCount].vertices[3] = (Vector2){ boxes[i].x + boxes[i].width, boxes[i].y };
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lights[slot].shadowCount++;
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}
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lights[slot].valid = true;
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DrawLightMask(slot);
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return true;
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}
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// Set up some boxes
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void SetupBoxes(Rectangle *boxes, int *count)
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{
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boxes[0] = (Rectangle){ 150,80, 40, 40 };
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boxes[1] = (Rectangle){ 1200, 700, 40, 40 };
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boxes[2] = (Rectangle){ 200, 600, 40, 40 };
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boxes[3] = (Rectangle){ 1000, 50, 40, 40 };
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boxes[4] = (Rectangle){ 500, 350, 40, 40 };
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for (int i = 5; i < MAX_BOXES; i++)
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{
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boxes[i] = (Rectangle){(float)GetRandomValue(0,GetScreenWidth()), (float)GetRandomValue(0,GetScreenHeight()), (float)GetRandomValue(10,100), (float)GetRandomValue(10,100) };
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}
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*count = MAX_BOXES;
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}
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//------------------------------------------------------------------------------------
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// Program main entry point
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//------------------------------------------------------------------------------------
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int main(void)
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{
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// Initialization
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//--------------------------------------------------------------------------------------
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const int screenWidth = 800;
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const int screenHeight = 450;
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InitWindow(screenWidth, screenHeight, "raylib [shapes] example - top down lights");
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// Initialize our 'world' of boxes
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int boxCount = 0;
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Rectangle boxes[MAX_BOXES] = { 0 };
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SetupBoxes(boxes, &boxCount);
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// Create a checkerboard ground texture
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Image img = GenImageChecked(64, 64, 32, 32, DARKBROWN, DARKGRAY);
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Texture2D backgroundTexture = LoadTextureFromImage(img);
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UnloadImage(img);
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// Create a global light mask to hold all the blended lights
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RenderTexture lightMask = LoadRenderTexture(GetScreenWidth(), GetScreenHeight());
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// Setup initial light
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SetupLight(0, 600, 400, 300);
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int nextLight = 1;
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bool showLines = false;
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SetTargetFPS(60); // Set our game to run at 60 frames-per-second
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//--------------------------------------------------------------------------------------
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// Main game loop
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while (!WindowShouldClose()) // Detect window close button or ESC key
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{
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// Update
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//----------------------------------------------------------------------------------
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// Drag light 0
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if (IsMouseButtonDown(MOUSE_BUTTON_LEFT)) MoveLight(0, GetMousePosition().x, GetMousePosition().y);
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// Make a new light
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if (IsMouseButtonPressed(MOUSE_BUTTON_RIGHT) && (nextLight < MAX_LIGHTS))
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{
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SetupLight(nextLight, GetMousePosition().x, GetMousePosition().y, 200);
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nextLight++;
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}
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// Toggle debug info
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if (IsKeyPressed(KEY_F1)) showLines = !showLines;
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// Update the lights and keep track if any were dirty so we know if we need to update the master light mask
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bool dirtyLights = false;
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for (int i = 0; i < MAX_LIGHTS; i++)
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{
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if (UpdateLight(i, boxes, boxCount)) dirtyLights = true;
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}
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// Update the light mask
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if (dirtyLights)
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{
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// Build up the light mask
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BeginTextureMode(lightMask);
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ClearBackground(BLACK);
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// Force the blend mode to only set the alpha of the destination
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rlSetBlendFactors(RLGL_SRC_ALPHA, RLGL_SRC_ALPHA, RLGL_MIN);
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rlSetBlendMode(BLEND_CUSTOM);
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// Merge in all the light masks
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for (int i = 0; i < MAX_LIGHTS; i++)
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{
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if (lights[i].active) DrawTextureRec(lights[i].mask.texture, (Rectangle){ 0, 0, (float)GetScreenWidth(), -(float)GetScreenHeight() }, Vector2Zero(), WHITE);
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}
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rlDrawRenderBatchActive();
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// Go back to normal blend
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rlSetBlendMode(BLEND_ALPHA);
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EndTextureMode();
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}
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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BeginDrawing();
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ClearBackground(BLACK);
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// Draw the tile background
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DrawTextureRec(backgroundTexture, (Rectangle){ 0, 0, (float)GetScreenWidth(), (float)GetScreenHeight() }, Vector2Zero(), WHITE);
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// Overlay the shadows from all the lights
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DrawTextureRec(lightMask.texture, (Rectangle){ 0, 0, (float)GetScreenWidth(), -(float)GetScreenHeight() }, Vector2Zero(), ColorAlpha(WHITE, showLines? 0.75f : 1.0f));
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// Draw the lights
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for (int i = 0; i < MAX_LIGHTS; i++)
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{
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if (lights[i].active) DrawCircle((int)lights[i].position.x, (int)lights[i].position.y, 10, (i == 0)? YELLOW : WHITE);
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}
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if (showLines)
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{
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for (int s = 0; s < lights[0].shadowCount; s++)
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{
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DrawTriangleFan(lights[0].shadows[s].vertices, 4, DARKPURPLE);
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}
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for (int b = 0; b < boxCount; b++)
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{
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if (CheckCollisionRecs(boxes[b],lights[0].bounds)) DrawRectangleRec(boxes[b], PURPLE);
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DrawRectangleLines((int)boxes[b].x, (int)boxes[b].y, (int)boxes[b].width, (int)boxes[b].height, DARKBLUE);
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}
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DrawText("(F1) Hide Shadow Volumes", 10, 50, 10, GREEN);
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}
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else
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{
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DrawText("(F1) Show Shadow Volumes", 10, 50, 10, GREEN);
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}
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DrawFPS(screenWidth - 80, 10);
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DrawText("Drag to move light #1", 10, 10, 10, DARKGREEN);
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DrawText("Right click to add new light", 10, 30, 10, DARKGREEN);
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EndDrawing();
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//----------------------------------------------------------------------------------
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}
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// De-Initialization
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//--------------------------------------------------------------------------------------
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UnloadTexture(backgroundTexture);
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UnloadRenderTexture(lightMask);
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for (int i = 0; i < MAX_LIGHTS; i++)
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{
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if (lights[i].active) UnloadRenderTexture(lights[i].mask);
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}
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CloseWindow(); // Close window and OpenGL context
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//--------------------------------------------------------------------------------------
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return 0;
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} |