raylib/examples/shaders/shaders_palette_switch.c
2019-05-20 16:36:42 +02:00

148 lines
5.4 KiB
C

/*******************************************************************************************
*
* raylib [shaders] example - Color palette switch
*
* NOTE: This example requires raylib OpenGL 3.3 or ES2 versions for shaders support,
* OpenGL 1.1 does not support shaders, recompile raylib to OpenGL 3.3 version.
*
* NOTE: Shaders used in this example are #version 330 (OpenGL 3.3), to test this example
* on OpenGL ES 2.0 platforms (Android, Raspberry Pi, HTML5), use #version 100 shaders
* raylib comes with shaders ready for both versions, check raylib/shaders install folder
*
* This example has been created using raylib 2.3 (www.raylib.com)
* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
* Example contributed by Marco Lizza (@MarcoLizza) and reviewed by Ramon Santamaria (@raysan5)
*
* Copyright (c) 2019 Marco Lizza (@MarcoLizza) and Ramon Santamaria (@raysan5)
*
********************************************************************************************/
#include "raylib.h"
#if defined(PLATFORM_DESKTOP)
#define GLSL_VERSION 330
#else // PLATFORM_RPI, PLATFORM_ANDROID, PLATFORM_WEB
#define GLSL_VERSION 100
#endif
#define MAX_PALETTES 3
#define COLORS_PER_PALETTE 8
#define VALUES_PER_COLOR 3
static const int palettes[MAX_PALETTES][COLORS_PER_PALETTE*VALUES_PER_COLOR] = {
{ // 3-BIT RGB
0, 0, 0,
255, 0, 0,
0, 255, 0,
0, 0, 255,
0, 255, 255,
255, 0, 255,
255, 255, 0,
255, 255, 255,
},
{ // AMMO-8 (GameBoy-like)
4, 12, 6,
17, 35, 24,
30, 58, 41,
48, 93, 66,
77, 128, 97,
137, 162, 87,
190, 220, 127,
238, 255, 204,
},
{ // RKBV (2-strip film)
21, 25, 26,
138, 76, 88,
217, 98, 117,
230, 184, 193,
69, 107, 115,
75, 151, 166,
165, 189, 194,
255, 245, 247,
}
};
static const char *paletteText[] = {
"3-BIT RGB",
"AMMO-8 (GameBoy-like)",
"RKBV (2-strip film)"
};
int main(void)
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib [shaders] example - color palette switch");
// Load shader to be used on some parts drawing
// NOTE 1: Using GLSL 330 shader version, on OpenGL ES 2.0 use GLSL 100 shader version
// NOTE 2: Defining 0 (NULL) for vertex shader forces usage of internal default vertex shader
Shader shader = LoadShader(0, FormatText("resources/shaders/glsl%i/palette_switch.fs", GLSL_VERSION));
// Get variable (uniform) location on the shader to connect with the program
// NOTE: If uniform variable could not be found in the shader, function returns -1
int paletteLoc = GetShaderLocation(shader, "palette");
int currentPalette = 0;
int lineHeight = screenHeight/COLORS_PER_PALETTE;
SetTargetFPS(60); // Set our game to run at 60 frames-per-second
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
// Update
//----------------------------------------------------------------------------------
if (IsKeyPressed(KEY_RIGHT)) currentPalette++;
else if (IsKeyPressed(KEY_LEFT)) currentPalette--;
if (currentPalette >= MAX_PALETTES) currentPalette = 0;
else if (currentPalette < 0) currentPalette = MAX_PALETTES - 1;
// Send new value to the shader to be used on drawing.
// NOTE: We are sending RGB triplets w/o the alpha channel
SetShaderValueV(shader, paletteLoc, palettes[currentPalette], UNIFORM_IVEC3, COLORS_PER_PALETTE);
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(RAYWHITE);
BeginShaderMode(shader);
for (int i = 0; i < COLORS_PER_PALETTE; i++)
{
// Draw horizontal screen-wide rectangles with increasing "palette index"
// The used palette index is encoded in the RGB components of the pixel
DrawRectangle(0, lineHeight*i, GetScreenWidth(), lineHeight, (Color){ i, i, i, 255 });
}
EndShaderMode();
DrawText("< >", 10, 10, 30, DARKBLUE);
DrawText("CURRENT PALETTE:", 60, 15, 20, RAYWHITE);
DrawText(paletteText[currentPalette], 300, 15, 20, RED);
DrawFPS(700, 15);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
UnloadShader(shader); // Unload shader
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}