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Nuklear/example/canvas.c

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/* nuklear - v1.05 - public domain */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdarg.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include <time.h>
#include <limits.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#define NK_PRIVATE
#define NK_INCLUDE_FIXED_TYPES
#define NK_INCLUDE_STANDARD_IO
#define NK_INCLUDE_DEFAULT_ALLOCATOR
#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
#define NK_INCLUDE_FONT_BAKING
#define NK_INCLUDE_DEFAULT_FONT
#define NK_IMPLEMENTATION
#include "../nuklear.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
/* macros */
#define WINDOW_WIDTH 1200
#define WINDOW_HEIGHT 800
#define MAX_VERTEX_MEMORY 512 * 1024
#define MAX_ELEMENT_MEMORY 128 * 1024
#define UNUSED(a) (void)a
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) < (b) ? (b) : (a))
#define LEN(a) (sizeof(a)/sizeof(a)[0])
#define NK_SHADER_VERSION "#version 150\n"
/* ===============================================================
*
* DEVICE
*
* ===============================================================*/
struct nk_glfw_vertex {
float position[2];
float uv[2];
nk_byte col[4];
};
struct device {
struct nk_buffer cmds;
struct nk_draw_null_texture null;
GLuint vbo, vao, ebo;
GLuint prog;
GLuint vert_shdr;
GLuint frag_shdr;
GLint attrib_pos;
GLint attrib_uv;
GLint attrib_col;
GLint uniform_tex;
GLint uniform_proj;
GLuint font_tex;
};
static void
die(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fputs("\n", stderr);
exit(EXIT_FAILURE);
}
/* function icon_load () is not used to build this file but might still be useful :) */
/*
static struct nk_image
icon_load(const char *filename)
{
int x,y,n;
GLuint tex;
unsigned char *data = stbi_load(filename, &x, &y, &n, 0);
if (!data) die("[SDL]: failed to load image: %s", filename);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
stbi_image_free(data);
return nk_image_id((int)tex);
}
*/
static void
device_init(struct device *dev)
{
GLint status;
static const GLchar *vertex_shader =
NK_SHADER_VERSION
"uniform mat4 ProjMtx;\n"
"in vec2 Position;\n"
"in vec2 TexCoord;\n"
"in vec4 Color;\n"
"out vec2 Frag_UV;\n"
"out vec4 Frag_Color;\n"
"void main() {\n"
" Frag_UV = TexCoord;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n"
"}\n";
static const GLchar *fragment_shader =
NK_SHADER_VERSION
"precision mediump float;\n"
"uniform sampler2D Texture;\n"
"in vec2 Frag_UV;\n"
"in vec4 Frag_Color;\n"
"out vec4 Out_Color;\n"
"void main(){\n"
" Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
"}\n";
nk_buffer_init_default(&dev->cmds);
dev->prog = glCreateProgram();
dev->vert_shdr = glCreateShader(GL_VERTEX_SHADER);
dev->frag_shdr = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(dev->vert_shdr, 1, &vertex_shader, 0);
glShaderSource(dev->frag_shdr, 1, &fragment_shader, 0);
glCompileShader(dev->vert_shdr);
glCompileShader(dev->frag_shdr);
glGetShaderiv(dev->vert_shdr, GL_COMPILE_STATUS, &status);
assert(status == GL_TRUE);
glGetShaderiv(dev->frag_shdr, GL_COMPILE_STATUS, &status);
assert(status == GL_TRUE);
glAttachShader(dev->prog, dev->vert_shdr);
glAttachShader(dev->prog, dev->frag_shdr);
glLinkProgram(dev->prog);
glGetProgramiv(dev->prog, GL_LINK_STATUS, &status);
assert(status == GL_TRUE);
dev->uniform_tex = glGetUniformLocation(dev->prog, "Texture");
dev->uniform_proj = glGetUniformLocation(dev->prog, "ProjMtx");
dev->attrib_pos = glGetAttribLocation(dev->prog, "Position");
dev->attrib_uv = glGetAttribLocation(dev->prog, "TexCoord");
dev->attrib_col = glGetAttribLocation(dev->prog, "Color");
{
/* buffer setup */
GLsizei vs = sizeof(struct nk_glfw_vertex);
size_t vp = offsetof(struct nk_glfw_vertex, position);
size_t vt = offsetof(struct nk_glfw_vertex, uv);
size_t vc = offsetof(struct nk_glfw_vertex, col);
glGenBuffers(1, &dev->vbo);
glGenBuffers(1, &dev->ebo);
glGenVertexArrays(1, &dev->vao);
glBindVertexArray(dev->vao);
glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);
glEnableVertexAttribArray((GLuint)dev->attrib_pos);
glEnableVertexAttribArray((GLuint)dev->attrib_uv);
glEnableVertexAttribArray((GLuint)dev->attrib_col);
glVertexAttribPointer((GLuint)dev->attrib_pos, 2, GL_FLOAT, GL_FALSE, vs, (void*)vp);
glVertexAttribPointer((GLuint)dev->attrib_uv, 2, GL_FLOAT, GL_FALSE, vs, (void*)vt);
glVertexAttribPointer((GLuint)dev->attrib_col, 4, GL_UNSIGNED_BYTE, GL_TRUE, vs, (void*)vc);
}
glBindTexture(GL_TEXTURE_2D, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
static void
device_upload_atlas(struct device *dev, const void *image, int width, int height)
{
glGenTextures(1, &dev->font_tex);
glBindTexture(GL_TEXTURE_2D, dev->font_tex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)width, (GLsizei)height, 0,
GL_RGBA, GL_UNSIGNED_BYTE, image);
}
static void
device_shutdown(struct device *dev)
{
glDetachShader(dev->prog, dev->vert_shdr);
glDetachShader(dev->prog, dev->frag_shdr);
glDeleteShader(dev->vert_shdr);
glDeleteShader(dev->frag_shdr);
glDeleteProgram(dev->prog);
glDeleteTextures(1, &dev->font_tex);
glDeleteBuffers(1, &dev->vbo);
glDeleteBuffers(1, &dev->ebo);
nk_buffer_free(&dev->cmds);
}
static void
device_draw(struct device *dev, struct nk_context *ctx, int width, int height,
enum nk_anti_aliasing AA)
{
GLfloat ortho[4][4] = {
{2.0f, 0.0f, 0.0f, 0.0f},
{0.0f,-2.0f, 0.0f, 0.0f},
{0.0f, 0.0f,-1.0f, 0.0f},
{-1.0f,1.0f, 0.0f, 1.0f},
};
ortho[0][0] /= (GLfloat)width;
ortho[1][1] /= (GLfloat)height;
/* setup global state */
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
glActiveTexture(GL_TEXTURE0);
/* setup program */
glUseProgram(dev->prog);
glUniform1i(dev->uniform_tex, 0);
glUniformMatrix4fv(dev->uniform_proj, 1, GL_FALSE, &ortho[0][0]);
{
/* convert from command queue into draw list and draw to screen */
const struct nk_draw_command *cmd;
void *vertices, *elements;
const nk_draw_index *offset = NULL;
/* allocate vertex and element buffer */
glBindVertexArray(dev->vao);
glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);
glBufferData(GL_ARRAY_BUFFER, MAX_VERTEX_MEMORY, NULL, GL_STREAM_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, MAX_ELEMENT_MEMORY, NULL, GL_STREAM_DRAW);
/* load draw vertices & elements directly into vertex + element buffer */
vertices = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
elements = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_WRITE_ONLY);
{
/* fill convert configuration */
struct nk_convert_config config;
static const struct nk_draw_vertex_layout_element vertex_layout[] = {
{NK_VERTEX_POSITION, NK_FORMAT_FLOAT, NK_OFFSETOF(struct nk_glfw_vertex, position)},
{NK_VERTEX_TEXCOORD, NK_FORMAT_FLOAT, NK_OFFSETOF(struct nk_glfw_vertex, uv)},
{NK_VERTEX_COLOR, NK_FORMAT_R8G8B8A8, NK_OFFSETOF(struct nk_glfw_vertex, col)},
{NK_VERTEX_LAYOUT_END}
};
NK_MEMSET(&config, 0, sizeof(config));
config.vertex_layout = vertex_layout;
config.vertex_size = sizeof(struct nk_glfw_vertex);
config.vertex_alignment = NK_ALIGNOF(struct nk_glfw_vertex);
config.null = dev->null;
config.circle_segment_count = 22;
config.curve_segment_count = 22;
config.arc_segment_count = 22;
config.global_alpha = 1.0f;
config.shape_AA = AA;
config.line_AA = AA;
/* setup buffers to load vertices and elements */
{struct nk_buffer vbuf, ebuf;
nk_buffer_init_fixed(&vbuf, vertices, MAX_VERTEX_MEMORY);
nk_buffer_init_fixed(&ebuf, elements, MAX_ELEMENT_MEMORY);
nk_convert(ctx, &dev->cmds, &vbuf, &ebuf, &config);}
}
glUnmapBuffer(GL_ARRAY_BUFFER);
glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);
/* iterate over and execute each draw command */
nk_draw_foreach(cmd, ctx, &dev->cmds)
{
if (!cmd->elem_count) continue;
glBindTexture(GL_TEXTURE_2D, (GLuint)cmd->texture.id);
glScissor(
(GLint)(cmd->clip_rect.x),
(GLint)((height - (GLint)(cmd->clip_rect.y + cmd->clip_rect.h))),
(GLint)(cmd->clip_rect.w),
(GLint)(cmd->clip_rect.h));
glDrawElements(GL_TRIANGLES, (GLsizei)cmd->elem_count, GL_UNSIGNED_SHORT, offset);
offset += cmd->elem_count;
}
nk_clear(ctx);
nk_buffer_clear(&dev->cmds);
}
/* default OpenGL state */
glUseProgram(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindVertexArray(0);
glDisable(GL_BLEND);
glDisable(GL_SCISSOR_TEST);
}
/* glfw callbacks (I don't know if there is a easier way to access text and scroll )*/
static void error_callback(int e, const char *d){printf("Error %d: %s\n", e, d);}
static void text_input(GLFWwindow *win, unsigned int codepoint)
{nk_input_unicode((struct nk_context*)glfwGetWindowUserPointer(win), codepoint);}
static void scroll_input(GLFWwindow *win, double _, double yoff)
{UNUSED(_);nk_input_scroll((struct nk_context*)glfwGetWindowUserPointer(win), nk_vec2(0, (float)yoff));}
static void
pump_input(struct nk_context *ctx, GLFWwindow *win)
{
double x, y;
nk_input_begin(ctx);
glfwPollEvents();
nk_input_key(ctx, NK_KEY_DEL, glfwGetKey(win, GLFW_KEY_DELETE) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_ENTER, glfwGetKey(win, GLFW_KEY_ENTER) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_TAB, glfwGetKey(win, GLFW_KEY_TAB) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_BACKSPACE, glfwGetKey(win, GLFW_KEY_BACKSPACE) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_LEFT, glfwGetKey(win, GLFW_KEY_LEFT) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_RIGHT, glfwGetKey(win, GLFW_KEY_RIGHT) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_UP, glfwGetKey(win, GLFW_KEY_UP) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_DOWN, glfwGetKey(win, GLFW_KEY_DOWN) == GLFW_PRESS);
if (glfwGetKey(win, GLFW_KEY_LEFT_CONTROL) == GLFW_PRESS ||
glfwGetKey(win, GLFW_KEY_RIGHT_CONTROL) == GLFW_PRESS) {
nk_input_key(ctx, NK_KEY_COPY, glfwGetKey(win, GLFW_KEY_C) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_PASTE, glfwGetKey(win, GLFW_KEY_P) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_CUT, glfwGetKey(win, GLFW_KEY_X) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_CUT, glfwGetKey(win, GLFW_KEY_E) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_SHIFT, 1);
} else {
nk_input_key(ctx, NK_KEY_COPY, 0);
nk_input_key(ctx, NK_KEY_PASTE, 0);
nk_input_key(ctx, NK_KEY_CUT, 0);
nk_input_key(ctx, NK_KEY_SHIFT, 0);
}
glfwGetCursorPos(win, &x, &y);
nk_input_motion(ctx, (int)x, (int)y);
nk_input_button(ctx, NK_BUTTON_LEFT, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS);
nk_input_button(ctx, NK_BUTTON_MIDDLE, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_MIDDLE) == GLFW_PRESS);
nk_input_button(ctx, NK_BUTTON_RIGHT, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_RIGHT) == GLFW_PRESS);
nk_input_end(ctx);
}
struct nk_canvas {
struct nk_command_buffer *painter;
struct nk_vec2 item_spacing;
struct nk_vec2 panel_padding;
struct nk_style_item window_background;
};
static void
canvas_begin(struct nk_context *ctx, struct nk_canvas *canvas, nk_flags flags,
int x, int y, int width, int height, struct nk_color background_color)
{
/* save style properties which will be overwritten */
canvas->panel_padding = ctx->style.window.padding;
canvas->item_spacing = ctx->style.window.spacing;
canvas->window_background = ctx->style.window.fixed_background;
/* use the complete window space and set background */
ctx->style.window.spacing = nk_vec2(0,0);
ctx->style.window.padding = nk_vec2(0,0);
ctx->style.window.fixed_background = nk_style_item_color(background_color);
/* create/update window and set position + size */
flags = flags & ~NK_WINDOW_DYNAMIC;
nk_window_set_bounds(ctx, "Window", nk_rect(x, y, width, height));
nk_begin(ctx, "Window", nk_rect(x, y, width, height), NK_WINDOW_NO_SCROLLBAR|flags);
/* allocate the complete window space for drawing */
{struct nk_rect total_space;
total_space = nk_window_get_content_region(ctx);
nk_layout_row_dynamic(ctx, total_space.h, 1);
nk_widget(&total_space, ctx);
canvas->painter = nk_window_get_canvas(ctx);}
}
static void
canvas_end(struct nk_context *ctx, struct nk_canvas *canvas)
{
nk_end(ctx);
ctx->style.window.spacing = canvas->panel_padding;
ctx->style.window.padding = canvas->item_spacing;
ctx->style.window.fixed_background = canvas->window_background;
}
int main(int argc, char *argv[])
{
/* Platform */
static GLFWwindow *win;
int width = 0, height = 0;
/* GUI */
struct device device;
struct nk_font_atlas atlas;
struct nk_context ctx;
/* GLFW */
glfwSetErrorCallback(error_callback);
if (!glfwInit()) {
fprintf(stdout, "[GFLW] failed to init!\n");
exit(1);
}
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
win = glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "Demo", NULL, NULL);
glfwMakeContextCurrent(win);
glfwSetWindowUserPointer(win, &ctx);
glfwSetCharCallback(win, text_input);
glfwSetScrollCallback(win, scroll_input);
glfwGetWindowSize(win, &width, &height);
/* OpenGL */
glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);
glewExperimental = 1;
if (glewInit() != GLEW_OK) {
fprintf(stderr, "Failed to setup GLEW\n");
exit(1);
}
/* GUI */
{device_init(&device);
{const void *image; int w, h;
struct nk_font *font;
nk_font_atlas_init_default(&atlas);
nk_font_atlas_begin(&atlas);
font = nk_font_atlas_add_default(&atlas, 13, 0);
image = nk_font_atlas_bake(&atlas, &w, &h, NK_FONT_ATLAS_RGBA32);
device_upload_atlas(&device, image, w, h);
nk_font_atlas_end(&atlas, nk_handle_id((int)device.font_tex), &device.null);
nk_init_default(&ctx, &font->handle);
glEnable(GL_TEXTURE_2D);
while (!glfwWindowShouldClose(win))
{
/* input */
pump_input(&ctx, win);
/* draw */
{struct nk_canvas canvas;
canvas_begin(&ctx, &canvas, 0, 0, 0, width, height, nk_rgb(250,250,250));
{
nk_fill_rect(canvas.painter, nk_rect(15,15,210,210), 5, nk_rgb(247, 230, 154));
nk_fill_rect(canvas.painter, nk_rect(20,20,200,200), 5, nk_rgb(188, 174, 118));
nk_draw_text(canvas.painter, nk_rect(30, 30, 150, 20), "Text to draw", 12, &font->handle, nk_rgb(188,174,118), nk_rgb(0,0,0));
nk_fill_rect(canvas.painter, nk_rect(250,20,100,100), 0, nk_rgb(0,0,255));
nk_fill_circle(canvas.painter, nk_rect(20,250,100,100), nk_rgb(255,0,0));
nk_fill_triangle(canvas.painter, 250, 250, 350, 250, 300, 350, nk_rgb(0,255,0));
nk_fill_arc(canvas.painter, 300, 180, 50, 0, 3.141592654f * 3.0f / 4.0f, nk_rgb(255,255,0));
{float points[12];
points[0] = 200; points[1] = 250;
points[2] = 250; points[3] = 350;
points[4] = 225; points[5] = 350;
points[6] = 200; points[7] = 300;
points[8] = 175; points[9] = 350;
points[10] = 150; points[11] = 350;
nk_fill_polygon(canvas.painter, points, 6, nk_rgb(0,0,0));}
nk_stroke_line(canvas.painter, 15, 10, 200, 10, 2.0f, nk_rgb(189,45,75));
nk_stroke_rect(canvas.painter, nk_rect(370, 20, 100, 100), 10, 3, nk_rgb(0,0,255));
nk_stroke_curve(canvas.painter, 380, 200, 405, 270, 455, 120, 480, 200, 2, nk_rgb(0,150,220));
nk_stroke_circle(canvas.painter, nk_rect(20, 370, 100, 100), 5, nk_rgb(0,255,120));
nk_stroke_triangle(canvas.painter, 370, 250, 470, 250, 420, 350, 6, nk_rgb(255,0,143));
}
canvas_end(&ctx, &canvas);}
/* Draw */
/* Framebuffer size is used instead of window size because the window size is in screen coordinates instead of pixels.
* See https://www.glfw.org/docs/latest/window_guide.html#window_size for more info
*/
glfwGetFramebufferSize(win, &width, &height);
glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT);
glClearColor(0.2f, 0.2f, 0.2f, 1.0f);
device_draw(&device, &ctx, width, height, NK_ANTI_ALIASING_ON);
glfwSwapBuffers(win);
}}}
nk_font_atlas_clear(&atlas);
nk_free(&ctx);
device_shutdown(&device);
glfwTerminate();
return 0;
}
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