small modern gl geometry api

3 files changed, 148 insertions, 29 deletions

diff --git a/gl.c b/gl.c
index 023b852..41e29e5 100644
--- a/gl.c
+++ b/gl.c
@@ -26,6 +26,7 @@
 	do(ENABLEVERTEXATTRIBARRAY, EnableVertexAttribArray)\
 	do(DISABLEVERTEXATTRIBARRAY, DisableVertexAttribArray)\
 	do(GENVERTEXARRAYS, GenVertexArrays)\
+	do(DELETEVERTEXARRAYS, DeleteVertexArrays)\
 	do(BINDVERTEXARRAY, BindVertexArray)\
 	do(UNIFORM1F, Uniform1f)\
 	do(UNIFORM2F, Uniform2f)\
@@ -125,3 +126,87 @@ static GLint gl_uniform_loc(GLuint program, char const *uniform) {
 	return loc;
 }
 
+typedef struct {
+	v2 pos;
+	v4 color;
+} GLSimpleVertex;
+typedef struct {
+	GLSimpleVertex v1, v2, v3;
+} GLSimpleTriangle;
+
+static GLSimpleTriangle *gl_geometry_triangles;
+static GLuint gl_geometry_program;
+static GLuint gl_geometry_v_pos;
+static GLuint gl_geometry_v_color;
+static GLint  gl_geometry_u_window_size;
+static GLuint gl_geometry_vbo, gl_geometry_vao;
+
+static void gl_geometry_init(void) {
+	char const *vshader_code = "#version 110\n\
+	attribute vec2 v_pos;\n\
+	attribute vec4 v_color;\n\
+	varying vec4 color;\n\
+	uniform vec2 window_size;\n\
+	void main() {\n\
+		float x = v_pos.x / window_size.x * 2.0 - 1.0;\n\
+		float y = 1.0 - v_pos.y / window_size.y * 2.0;\n\
+		gl_Position = vec4(x, y, 0.0, 1.0);\n\
+		color = v_color;\n\
+	}\n\
+	";
+	char const *fshader_code = "#version 110\n\
+	varying vec4 color;\n\
+	void main() {\n\
+		gl_FragColor = color;\n\
+	}\n\
+	";
+
+	gl_geometry_program = gl_compile_and_link_shaders(vshader_code, fshader_code);
+	gl_geometry_v_pos = gl_attrib_loc(gl_geometry_program, "v_pos");
+	gl_geometry_v_color = gl_attrib_loc(gl_geometry_program, "v_color");
+	gl_geometry_u_window_size = gl_uniform_loc(gl_geometry_program, "window_size");
+
+	glGenBuffers(1, &gl_geometry_vbo);
+	if (gl_version_major >= 3)
+		glGenVertexArrays(1, &gl_geometry_vao);
+}
+
+static void gl_geometry_rect(Rect r, u32 color_rgba) {
+	v4 color = rgba_u32_to_v4(color_rgba);
+
+	v2 p1 = r.pos;
+	v2 p2 = v2_add(r.pos, V2(0, r.size.y));
+	v2 p3 = v2_add(r.pos, V2(r.size.x, r.size.y));
+	v2 p4 = p3;
+	v2 p5 = v2_add(r.pos, V2(r.size.x, 0));
+	v2 p6 = p1;
+	GLSimpleTriangle triangle = {
+		{p1, color},
+		{p2, color},
+		{p3, color}
+	};
+	arr_add(gl_geometry_triangles, triangle);
+	triangle.v1.pos = p4;
+	triangle.v2.pos = p5;
+	triangle.v3.pos = p6;
+	arr_add(gl_geometry_triangles, triangle);
+}
+
+static void gl_geometry_draw(Ted *ted) {
+	size_t ntriangles = arr_len(gl_geometry_triangles);
+	
+	if (gl_version_major >= 3)
+		glBindVertexArray(gl_geometry_vao);
+	glBindBuffer(GL_ARRAY_BUFFER, gl_geometry_vbo);
+	glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)(ntriangles * sizeof(GLSimpleTriangle)), gl_geometry_triangles, GL_STREAM_DRAW);
+	glVertexAttribPointer(gl_geometry_v_pos,   2, GL_FLOAT, 0, sizeof(GLSimpleVertex), (void *)offsetof(GLSimpleVertex, pos));
+	glEnableVertexAttribArray(gl_geometry_v_pos);
+	glVertexAttribPointer(gl_geometry_v_color, 4, GL_FLOAT, 0, sizeof(GLSimpleVertex), (void *)offsetof(GLSimpleVertex, color));
+	glEnableVertexAttribArray(gl_geometry_v_color);
+
+	glUseProgram(gl_geometry_program);
+	glUniform2f(gl_geometry_u_window_size, ted->window_width, ted->window_height);
+	glDrawArrays(GL_TRIANGLES, 0, (GLsizei)(3 * ntriangles));
+	
+	arr_clear(gl_geometry_triangles);
+}
diff --git a/main.c b/main.c
index 4e1ce89..49f4730 100644
--- a/main.c
+++ b/main.c
@@ -19,13 +19,10 @@ no_warn_end
 #if _WIN32
 #include <shellapi.h>
 #endif
-#include "gl.c"
+
 
 #include "unicode.h"
-#include "text.c"
 #include "util.c"
-#define MATH_GL
-#include "math.c"
 #if _WIN32
 #include "filesystem-win.c"
 #elif __unix__
@@ -33,14 +30,20 @@ no_warn_end
 #else
 #error "Unrecognized operating system."
 #endif
+#include "arr.c"
 
+#define MATH_GL
+#include "math.c"
 
+#include "text.h"
 #include "command.h"
 #include "colors.h"
 #include "time.c"
 #include "ted.h"
+#include "gl.c"
+#include "text.c"
+
 #include "string32.c"
-#include "arr.c"
 #include "syntax.c"
 #include "buffer.c"
 #include "ted.c"
@@ -278,32 +281,34 @@ int main(int argc, char **argv) {
 		}
 	}
 #endif
-
+	
+	gl_geometry_init();
+	
 	SDL_GL_SetSwapInterval(1); // vsync
-
-	char const *vshader_code = "#version 110\n\
-attribute vec2 v_pos;\n\
-attribute vec4 v_color;\n\
-varying vec4 color;\n\
-uniform vec2 window_size;\n\
-void main() {\n\
-	float x = v_pos.x / window_size.x * 2.0 - 1.0;\n\
-	float y = 1.0 - v_pos.y / window_size.y * 2.0;\n\
-	gl_Position = vec4(x, y, 0.0, 1.0);\n\
-	color = v_color;\n\
-}\n\
-";
-	char const *fshader_code = "#version 110\n\
-varying vec4 color;\n\
-void main() {\n\
-	gl_FragColor = color;\n\
-}\n\
-";
+	#if 0
 	float vertices[][6] = {
 		{0, 0,  1, 0, 0, 1},
 		{50, 0, 0, 1, 0, 1},
 		{0, 50, 0, 0, 1, 1},
 	};
+	char const *vshader_code = "#version 110\n\
+	attribute vec2 v_pos;\n\
+	attribute vec4 v_color;\n\
+	varying vec4 color;\n\
+	uniform vec2 window_size;\n\
+	void main() {\n\
+		float x = v_pos.x / window_size.x * 2.0 - 1.0;\n\
+		float y = 1.0 - v_pos.y / window_size.y * 2.0;\n\
+		gl_Position = vec4(x, y, 0.0, 1.0);\n\
+		color = v_color;\n\
+	}\n\
+	";
+	char const *fshader_code = "#version 110\n\
+	varying vec4 color;\n\
+	void main() {\n\
+		gl_FragColor = color;\n\
+	}\n\
+	";
 	GLuint program = gl_compile_and_link_shaders(vshader_code, fshader_code);
 	GLuint v_pos = gl_attrib_loc(program, "v_pos");
 	GLuint v_color = gl_attrib_loc(program, "v_color");
@@ -341,6 +346,29 @@ void main() {\n\
 		glDrawArrays(GL_TRIANGLES, 0, 3);
 		SDL_GL_SwapWindow(window);
 	}
+	#endif
+
+	while (1) {
+		int w, h;
+		SDL_GetWindowSize(window, &w, &h);
+		ted->window_width = (float)w;
+		ted->window_height = (float)h;
+
+		SDL_Event event;
+		while (SDL_PollEvent(&event)) if (event.type == SDL_QUIT) return 0;
+
+		glViewport(0, 0, w, h);
+		glClearColor(0,0,0,1);
+		glClear(GL_COLOR_BUFFER_BIT);
+
+		for (int i = 0; i < 20; ++i) {
+			gl_geometry_rect(rect(V2(0, 10*(float)i), V2(100, 100)), 0xffffffff >> i);
+		
+			gl_geometry_draw(ted);
+		}
+
+		SDL_GL_SwapWindow(window);
+	}
 
 	return 0;
 
diff --git a/math.c b/math.c
index 1443267..00735cf 100644
--- a/math.c
+++ b/math.c
@@ -772,10 +772,16 @@ static void gl_color2f(float v, float a) {
 }
 
 static void rgba_u32_to_floats(u32 rgba, float floats[4]) {
-	floats[0] = (float)(rgba >> 24) / 255.f;
-	floats[1] = (float)(rgba >> 16) / 255.f;
-	floats[2] = (float)(rgba >>  8) / 255.f;
-	floats[3] = (float)(rgba >>  0) / 255.f;
+	floats[0] = (float)((rgba >> 24) & 0xFF) / 255.f;
+	floats[1] = (float)((rgba >> 16) & 0xFF) / 255.f;
+	floats[2] = (float)((rgba >>  8) & 0xFF) / 255.f;
+	floats[3] = (float)((rgba >>  0) & 0xFF) / 255.f;
+}
+
+static v4 rgba_u32_to_v4(u32 rgba) {
+	float c[4];
+	rgba_u32_to_floats(rgba, c);
+	return V4(c[0], c[1], c[2], c[3]);
 }
 
 // color is 0xRRGGBBAA