"Cool" OpenGL Demo of a rectangle

examples/main.odin

@@ -1,5 +1,6 @@
 #load "basic.odin"
 #load "win32.odin"
+#load "opengl.odin"
 
 win32_perf_count_freq := GetQueryPerformanceFrequency();
 
@@ -26,10 +27,10 @@ win32_print_last_error :: proc() {
 main :: proc() {
 	instance := GetModuleHandleA(null);
 
-	class_name := "Odin-Language-Demo\x00";
-	title := "Odin Language Demo\x00";
+	class_name   := "Odin-Language-Demo\x00";
+	title        := "Odin Language Demo\x00";
 	c_class_name := ^class_name[0];
-	c_title := ^title[0];
+	c_title      := ^title[0];
 
 	wc := WNDCLASSEXA{
 		cbSize    = size_of(WNDCLASSEXA) as u32,
@@ -49,10 +50,14 @@ main :: proc() {
 		return;
 	}
 
+	WINDOW_WIDTH  :: 854;
+	WINDOW_HEIGHT :: 480;
+
 	hwnd := CreateWindowExA(0,
 	                        c_class_name, c_title,
 	                        WS_VISIBLE | WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX,
-	                        CW_USEDEFAULT, CW_USEDEFAULT, 854, 480,
+	                        CW_USEDEFAULT, CW_USEDEFAULT,
+	                        WINDOW_WIDTH, WINDOW_HEIGHT,
 	                        null, null, instance, null);
 
 
@@ -82,30 +87,25 @@ main :: proc() {
 		wglMakeCurrent(dc, opengl_context);
 
 		attribs := [8]i32{
-			0x2091, // WGL_CONTEXT_MAJOR_VERSION_ARB
-			2, // Major
-			0x2092, // WGL_CONTEXT_MINOR_VERSION_ARB
-			1, // Minor
-			0x9126, // WGL_CONTEXT_PROFILE_MASK_ARB
-			0x0002, // WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB
+			WGL_CONTEXT_MAJOR_VERSION_ARB, 2,
+			WGL_CONTEXT_MINOR_VERSION_ARB, 1,
+			WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB,
 			0, // NOTE(bill): tells the proc that this is the end of attribs
 		};
 
 		wgl_string := "wglCreateContextAttribsARB\x00";
-		wglCreateContextAttribsARB := wglGetProcAddress(^wgl_string[0]) as wglCreateContextAttribsARBType;
+		c_wgl_string := ^wgl_string[0];
+		wglCreateContextAttribsARB := wglGetProcAddress(c_wgl_string) as wglCreateContextAttribsARBType;
 		rc := wglCreateContextAttribsARB(dc, 0, ^attribs[0]);
 		wglMakeCurrent(dc, rc);
 		SwapBuffers(dc);
 	}
 
 	start_time := time_now();
-	running := false;
+	running := true;
 	for running {
 		curr_time := time_now();
 		dt := curr_time - start_time;
-		if dt > 2.0 {
-			running = false;
-		}
 
 		msg: MSG;
 		for {
@@ -115,14 +115,34 @@ main :: proc() {
 			}
 
 			if msg.message == WM_QUIT {
-				return;
-			} else {
-				_ = TranslateMessage(^msg);
-				_ = DispatchMessageA(^msg);
+				running = false;
+				break;
 			}
+			_ = TranslateMessage(^msg);
+			_ = DispatchMessageA(^msg);
+		}
+
+		glClearColor(0.5, 0.7, 1.0, 1.0);
+		glClear(GL_COLOR_BUFFER_BIT);
+		// glOrtho(0, WINDOW_WIDTH, 0, WINDOW_HEIGHT, -1, +1);
+
+		{
+			glBegin(GL_TRIANGLES);
+			defer glEnd();
+
+			glColor3f(1, 0, 0); glVertex3f(+0.5, -0.5, 0);
+			glColor3f(0, 1, 0); glVertex3f(+0.5, +0.5, 0);
+			glColor3f(0, 0, 1); glVertex3f(-0.5, +0.5, 0);
+
+			glColor3f(0, 0, 1); glVertex3f(-0.5, +0.5, 0);
+			glColor3f(1, 1, 0); glVertex3f(-0.5, -0.5, 0);
+			glColor3f(1, 0, 0); glVertex3f(+0.5, -0.5, 0);
 		}
 
 		SwapBuffers(dc);
-		sleep_ms(2);
+		{
+			ms := (16 - dt*1000) as i32;
+			if ms > 0 { sleep_ms(ms); }
+		}
 	}
 }

examples/opengl.odin

@@ -0,0 +1,46 @@
+GL_ZERO                 :: 0x0000;
+GL_ONE                  :: 0x0001;
+GL_TRIANGLES            :: 0x0004;
+GL_BLEND                :: 0x0BE2;
+GL_SRC_ALPHA            :: 0x0302;
+GL_ONE_MINUS_SRC_ALPHA  :: 0x0303;
+GL_TEXTURE_2D           :: 0x0DE1;
+GL_RGBA8                :: 0x8058;
+GL_UNSIGNED_BYTE        :: 0x1401;
+GL_BGRA_EXT             :: 0x80E1;
+GL_TEXTURE_MAX_LEVEL    :: 0x813D;
+GL_RGBA                 :: 0x1908;
+
+GL_NEAREST :: 0x2600;
+GL_LINEAR  :: 0x2601;
+
+GL_DEPTH_BUFFER_BIT   :: 0x00000100;
+GL_STENCIL_BUFFER_BIT :: 0x00000400;
+GL_COLOR_BUFFER_BIT   :: 0x00004000;
+
+GL_TEXTURE_MAX_ANISOTROPY_EXT :: 0x84FE;
+
+GL_TEXTURE_MAG_FILTER  :: 0x2800;
+GL_TEXTURE_MIN_FILTER  :: 0x2801;
+GL_TEXTURE_WRAP_S      :: 0x2802;
+GL_TEXTURE_WRAP_T      :: 0x2803;
+
+glClear         :: proc(mask: u32) #foreign
+glClearColor    :: proc(r, g, b, a: f32) #foreign
+glBegin         :: proc(mode: i32) #foreign
+glEnd           :: proc() #foreign
+glColor3f       :: proc(r, g, b: f32) #foreign
+glColor4f       :: proc(r, g, b, a: f32) #foreign
+glVertex3f      :: proc(x, y, z: f32) #foreign
+glTexCoord2f    :: proc(u, v: f32) #foreign
+glLoadIdentity  :: proc() #foreign
+glOrtho         :: proc(left, right, bottom, top, near, far: f64) #foreign
+glBlendFunc     :: proc(sfactor, dfactor: i32) #foreign
+glEnable        :: proc(cap: i32) #foreign
+glDisable       :: proc(cap: i32) #foreign
+glGenTextures   :: proc(count: i32, result: ^u32) #foreign
+glTexParameteri :: proc(target, pname, param: i32) #foreign
+glTexParameterf :: proc(target: i32, pname: i32, param: f32) #foreign
+glBindTexture   :: proc(target: i32, texture: u32) #foreign
+glTexImage2D    :: proc(target, level, internal_format, width, height, border, format, _type: i32, pixels: rawptr) #foreign
+

examples/win32.odin

@@ -178,8 +178,15 @@ type PIXELFORMATDESCRIPTOR: struct  {
 GetDC             :: proc(h: HANDLE) -> HDC #foreign
 SetPixelFormat    :: proc(hdc: HDC, pixel_format: i32, pfd: ^PIXELFORMATDESCRIPTOR ) -> BOOL #foreign
 ChoosePixelFormat :: proc(hdc: HDC, pfd: ^PIXELFORMATDESCRIPTOR) -> i32 #foreign
+SwapBuffers       :: proc(hdc: HDC) -> BOOL #foreign
+
+
+WGL_CONTEXT_MAJOR_VERSION_ARB             :: 0x2091;
+WGL_CONTEXT_MINOR_VERSION_ARB             :: 0x2092;
+WGL_CONTEXT_PROFILE_MASK_ARB              :: 0x9126;
+WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB :: 0x0002;
+
 wglCreateContext  :: proc(hdc: HDC) -> HGLRC #foreign
 wglMakeCurrent    :: proc(hdc: HDC, hglrc: HGLRC) -> BOOL #foreign
 wglGetProcAddress :: proc(c_str: ^u8) -> PROC #foreign
 wglDeleteContext  :: proc(hglrc: HGLRC) -> BOOL #foreign
-SwapBuffers       :: proc(hdc: HDC) -> BOOL #foreign