Stubbing out a GL backend

karl2d.odin

@@ -781,7 +781,7 @@ get_default_font :: proc() -> Font_Handle {
 //---------//
 
 load_shader :: proc(shader_source: string, layout_formats: []Pixel_Format = {}) -> Shader {
-	handle, desc := rb.load_shader(shader_source, s.frame_allocator, layout_formats)
+	handle, desc := rb.load_shader(shader_source, shader_source, s.frame_allocator, layout_formats)
 
 	if handle == SHADER_NONE {
 		log.error("Failed loading shader")

render_backend_d3d11.odin

@@ -47,7 +47,7 @@ d3d11_init :: proc(state: rawptr, window_handle: Window_Handle, swapchain_width,
 		._11_1,
 		._11_0,
 	}
-
+	
 	base_device: ^d3d11.IDevice
 	base_device_context: ^d3d11.IDeviceContext
 
@@ -409,10 +409,10 @@ d3d11_destroy_texture :: proc(th: Texture_Handle) {
 	hm.remove(&s.textures, th)
 }
 
-d3d11_load_shader :: proc(shader_source: string, desc_allocator := frame_allocator, layout_formats: []Pixel_Format = {}) -> (handle: Shader_Handle, desc: Shader_Desc) {
+d3d11_load_shader :: proc(vs_source: string, ps_source: string, desc_allocator := frame_allocator, layout_formats: []Pixel_Format = {}) -> (handle: Shader_Handle, desc: Shader_Desc) {
 	vs_blob: ^d3d11.IBlob
 	vs_blob_errors: ^d3d11.IBlob
-	ch(d3d_compiler.Compile(raw_data(shader_source), len(shader_source), nil, nil, nil, "vs_main", "vs_5_0", 0, 0, &vs_blob, &vs_blob_errors))
+	ch(d3d_compiler.Compile(raw_data(vs_source), len(vs_source), nil, nil, nil, "vs_main", "vs_5_0", 0, 0, &vs_blob, &vs_blob_errors))
 
 	if vs_blob_errors != nil {
 		log.error("Failed compiling shader:")
@@ -547,7 +547,7 @@ d3d11_load_shader :: proc(shader_source: string, desc_allocator := frame_allocat
 
 	ps_blob: ^d3d11.IBlob
 	ps_blob_errors: ^d3d11.IBlob
-	ch(d3d_compiler.Compile(raw_data(shader_source), len(shader_source), nil, nil, nil, "ps_main", "ps_5_0", 0, 0, &ps_blob, &ps_blob_errors))
+	ch(d3d_compiler.Compile(raw_data(ps_source), len(ps_source), nil, nil, nil, "ps_main", "ps_5_0", 0, 0, &ps_blob, &ps_blob_errors))
 
 	if ps_blob_errors != nil {
 		log.error("Failed compiling shader:")

render_backend_gl.odin

@@ -0,0 +1,112 @@
+#+build windows, darwin, linux
+#+private file
+
+package karl2d
+
+@(private="package")
+RENDER_BACKEND_INTERFACE_GL :: Render_Backend_Interface {
+	state_size = gl_state_size,
+	init = gl_init,
+	shutdown = gl_shutdown,
+	clear = gl_clear,
+	present = gl_present,
+	draw = gl_draw,
+	resize_swapchain = gl_resize_swapchain,
+	get_swapchain_width = gl_get_swapchain_width,
+	get_swapchain_height = gl_get_swapchain_height,
+	set_internal_state = gl_set_internal_state,
+	create_texture = gl_create_texture,
+	load_texture = gl_load_texture,
+	update_texture = gl_update_texture,
+	destroy_texture = gl_destroy_texture,
+	load_shader = gl_load_shader,
+	destroy_shader = gl_destroy_shader,
+}
+
+import "base:runtime"
+import gl "vendor:OpenGL"
+import glfw "vendor:glfw"
+
+GL_State :: struct {
+	width: int,
+	height: int,
+	allocator: runtime.Allocator,
+}
+
+s: ^GL_State
+
+gl_state_size :: proc() -> int {
+	return size_of(GL_State)
+}
+
+gl_init :: proc(state: rawptr, window_handle: Window_Handle, swapchain_width, swapchain_height: int, allocator := context.allocator) {
+	s = (^GL_State)(state)
+	s.width = swapchain_width
+	s.height = swapchain_height
+	s.allocator = allocator
+
+	gl.load_up_to(3, 3, glfw.gl_set_proc_address)
+
+}
+
+gl_shutdown :: proc() {
+}
+
+gl_clear :: proc(color: Color) {
+}
+
+gl_present :: proc() {
+}
+
+gl_draw :: proc(shd: Shader, texture: Texture_Handle, view_proj: Mat4, scissor: Maybe(Rect), vertex_buffer: []u8) {
+}
+
+gl_resize_swapchain :: proc(w, h: int) {
+}
+
+gl_get_swapchain_width :: proc() -> int {
+	return s.width
+}
+
+gl_get_swapchain_height :: proc() -> int {
+	return s.height
+}
+
+gl_set_internal_state :: proc(state: rawptr) {
+}
+
+gl_create_texture :: proc(width: int, height: int, format: Pixel_Format) -> Texture_Handle {
+	return {}
+}
+
+gl_load_texture :: proc(data: []u8, width: int, height: int, format: Pixel_Format) -> Texture_Handle {
+	return {}
+}
+
+gl_update_texture :: proc(th: Texture_Handle, data: []u8, rect: Rect) -> bool {
+	return false
+}
+
+gl_destroy_texture :: proc(th: Texture_Handle) {
+
+}
+
+gl_load_shader :: proc(vs_source: string, fs_source: string, desc_allocator := frame_allocator, layout_formats: []Pixel_Format = {}) -> (handle: Shader_Handle, desc: Shader_Desc) {
+	vs_id := gl.CreateShader(u32(gl.Shader_Type.VERTEX_SHADER))
+	vs_len := i32(len(vs_source))
+	vs_cstr := cstring(raw_data(vs_source))
+	gl.ShaderSource(vs_id, 1, &vs_cstr, &vs_len)
+	gl.CompileShader(vs_id)
+
+	fs_id := gl.CreateShader(u32(gl.Shader_Type.FRAGMENT_SHADER))
+	fs_len := i32(len(fs_source))
+	fs_cstr := cstring(raw_data(fs_source))
+	gl.ShaderSource(fs_id, 1, &fs_cstr, &fs_len)
+	gl.CompileShader(fs_id)
+
+	return {}, {}
+}
+
+gl_destroy_shader :: proc(h: Shader_Handle) {
+	
+}

render_backend_interface.odin

@@ -30,7 +30,7 @@ Render_Backend_Interface :: struct {
 	update_texture: proc(handle: Texture_Handle, data: []u8, rect: Rect) -> bool,
 	destroy_texture: proc(handle: Texture_Handle),
 
-	load_shader: proc(shader_source: string, desc_allocator := context.temp_allocator, layout_formats: []Pixel_Format = {}) -> (handle: Shader_Handle, desc: Shader_Desc),
+	load_shader: proc(vertex_shader_source: string, pixel_shader_source: string, desc_allocator := context.temp_allocator, layout_formats: []Pixel_Format = {}) -> (handle: Shader_Handle, desc: Shader_Desc),
 	destroy_shader: proc(shader: Shader_Handle),
 
 	resize_swapchain: proc(width, height: int),