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package opengl_backend
import "core:log"
import gl "vendor:OpenGL"
import bk ".."
@(private)
g_gl: ^OpenGL_State
OpenGL_State :: struct {
gl_ctx: GL_Context,
width: u32,
height: u32,
default_render_pass: bk.Render_Pass_Handle,
current_frame: u32,
current_pipeline: bk.Pipeline_Handle,
frame_active: bool,
render_pass_active: bool,
headless: bool,
push_constant_buffer: u32,
buffers: [MAX_BUFFERS]GL_Buffer_Entry,
textures: [MAX_TEXTURES]GL_Texture_Entry,
shaders: [MAX_SHADERS]GL_Shader_Entry,
pipelines: [MAX_PIPELINES]GL_Pipeline_Entry,
descriptors: [MAX_DESCRIPTORS]GL_Descriptor_Entry,
render_passes: [MAX_RENDER_PASSES]GL_Render_Pass_Entry,
framebuffers: [MAX_FRAMEBUFFERS]GL_Framebuffer_Entry,
samplers: [MAX_SAMPLERS]GL_Sampler_Entry,
}
MAX_BUFFERS :: 1024
MAX_TEXTURES :: 512
MAX_SHADERS :: 256
MAX_PIPELINES :: 128
MAX_DESCRIPTORS :: 512
MAX_RENDER_PASSES :: 32
MAX_FRAMEBUFFERS :: 64
MAX_SAMPLERS :: 64
OPENGL_BINDINGS_PER_GROUP :: 16
OPENGL_PUSH_CONSTANT_BINDING :: 15
PUSH_CONSTANT_MAX_SIZE :: 256
GL_Buffer_Entry :: struct {
id: u32,
size: u64,
usage: bk.Buffer_Usage_Flags,
memory: bk.Memory_Property_Flags,
mapped_ptr: rawptr,
active: bool,
}
GL_Texture_Entry :: struct {
id: u32,
width: u32,
height: u32,
format: bk.Format,
usage: bk.Image_Usage_Flags,
active: bool,
}
GL_Shader_Entry :: struct {
id: u32,
stage: bk.Shader_Stage,
active: bool,
}
GL_Pipeline_Entry :: struct {
program: u32,
vao: u32,
topology: u32,
enable_blending: bool,
blend_mode: bk.Blend_Mode,
enable_depth_test: bool,
enable_depth_bias: bool,
stencil: bk.Stencil_State,
cull_mode: bk.Cull_Mode,
front_face: bk.Front_Face,
vertex_stride: u32,
vertex_strides: [16]u32,
push_constant_size: u32,
push_constant_stages: bk.Shader_Stage_Flags,
is_compute: bool,
active: bool,
}
Descriptor_Kind :: enum {
Set_Layout,
Pool,
Set,
}
GL_Descriptor_Binding :: struct {
binding: u32,
type: bk.Descriptor_Type,
buffer: bk.Buffer_Handle,
texture: bk.Texture_Handle,
sampler: bk.Sampler_Handle,
buf_size: u64,
}
GL_Descriptor_Entry :: struct {
kind: Descriptor_Kind,
layout_bindings: [16]bk.Descriptor_Set_Layout_Binding,
layout_count: u32,
bindings: [16]GL_Descriptor_Binding,
binding_count: u32,
active: bool,
}
GL_Render_Pass_Entry :: struct {
desc: bk.Render_Pass_Desc,
active: bool,
}
GL_Framebuffer_Entry :: struct {
id: u32,
color_tex: bk.Texture_Handle,
color_texs: [bk.MAX_COLOR_TARGETS]bk.Texture_Handle,
color_count: u32,
depth_tex: bk.Texture_Handle,
width: u32,
height: u32,
active: bool,
}
GL_Sampler_Entry :: struct {
id: u32,
active: bool,
}
init_opengl_backend :: proc(
surface: bk.Surface_Desc,
width, height: u32,
title: cstring,
) -> (
backend: bk.Backend,
ok: bool,
) {
state := new(OpenGL_State)
if state == nil {
log.error("gpu/opengl: failed to allocate OpenGL state")
return {}, false
}
g_gl = state
gl_ctx, context_ok := create_gl_context(surface, width, height, title)
if !context_ok {
log.error("gpu/opengl: failed to create OpenGL 4.5 core context")
free(state)
g_gl = nil
return {}, false
}
state.gl_ctx = gl_ctx
state.headless = gl_ctx.headless
state.width = width
state.height = height
state.default_render_pass = bk.Render_Pass_Handle(1)
state.render_passes[1].desc = {
has_color = true,
has_depth = true,
color_format = .R8G8B8A8_UNORM,
depth_format = .D32_SFLOAT,
}
state.render_passes[1].active = true
gl.load_up_to(4, 5, gl_context_set_proc_address)
gl.ClipControl(gl.UPPER_LEFT, gl.ZERO_TO_ONE)
gl.Disable(gl.DEPTH_TEST)
gl.Disable(gl.SCISSOR_TEST)
gl.Disable(gl.BLEND)
gl.CreateBuffers(1, &state.push_constant_buffer)
gl.NamedBufferData(state.push_constant_buffer, PUSH_CONSTANT_MAX_SIZE, nil, gl.DYNAMIC_DRAW)
backend = bk.Backend {
capabilities = bk.implemented_base_capabilities(
bk.MAX_COLOR_TARGETS,
PUSH_CONSTANT_MAX_SIZE,
),
shutdown = shutdown_opengl,
wait_idle = wait_idle_opengl,
begin_frame = begin_frame_opengl,
end_frame = end_frame_opengl,
on_resize = on_resize_opengl,
get_extent = get_extent_opengl,
current_frame_index = current_frame_index_opengl,
begin_render_pass = begin_render_pass_opengl,
begin_default_pass = begin_default_pass_opengl,
end_render_pass = end_render_pass_opengl,
set_viewport = set_viewport_opengl,
set_scissor = set_scissor_opengl,
set_depth_bias = set_depth_bias_opengl,
create_graphics_pipeline = create_graphics_pipeline_opengl,
destroy_graphics_pipeline = destroy_graphics_pipeline_opengl,
bind_graphics_pipeline = bind_graphics_pipeline_opengl,
push_constants = push_constants_opengl,
create_buffer = create_buffer_opengl,
create_buffer_staged = create_buffer_staged_opengl,
destroy_buffer = destroy_buffer_opengl,
map_buffer = map_buffer_opengl,
unmap_buffer = unmap_buffer_opengl,
get_buffer_mapped = get_buffer_mapped_opengl,
bind_vertex_buffer = bind_vertex_buffer_opengl,
bind_vertex_buffer_slot = bind_vertex_buffer_slot_opengl,
bind_index_buffer = bind_index_buffer_opengl,
create_texture = create_texture_opengl,
destroy_texture = destroy_texture_opengl,
read_texture_rgba8 = read_texture_rgba8_opengl,
create_sampler = create_sampler_opengl,
destroy_sampler = destroy_sampler_opengl,
create_image = create_image_opengl,
create_image_view = create_image_view_opengl,
destroy_image = destroy_image_opengl,
create_descriptor_set_layout = create_descriptor_set_layout_opengl,
destroy_descriptor_set_layout = destroy_descriptor_set_layout_opengl,
create_descriptor_pool = create_descriptor_pool_opengl,
destroy_descriptor_pool = destroy_descriptor_pool_opengl,
allocate_descriptor_set = allocate_descriptor_set_opengl,
bind_descriptor_set = bind_descriptor_set_opengl,
update_descriptor_image = update_descriptor_image_opengl,
update_descriptor_buffer = update_descriptor_buffer_opengl,
create_render_pass = create_render_pass_opengl,
destroy_render_pass = destroy_render_pass_opengl,
create_framebuffer = create_framebuffer_opengl,
destroy_framebuffer = destroy_framebuffer_opengl,
create_shader_module = create_shader_module_opengl,
destroy_shader = destroy_shader_opengl,
draw = draw_opengl,
draw_indexed = draw_indexed_opengl,
draw_indirect = draw_indirect_opengl,
draw_indexed_indirect = draw_indexed_indirect_opengl,
create_compute_pipeline = create_compute_pipeline_opengl,
destroy_compute_pipeline = destroy_compute_pipeline_opengl,
bind_compute_pipeline = bind_compute_pipeline_opengl,
dispatch_compute = dispatch_compute_opengl,
compute_barrier = compute_barrier_opengl,
get_default_render_pass = get_default_render_pass_opengl,
get_depth_format = get_depth_format_opengl,
}
bk.backend_initialized = true
return backend, true
}
shutdown_opengl :: proc() {
if g_gl == nil do return
if g_gl.push_constant_buffer != 0 {
id := g_gl.push_constant_buffer
gl.DeleteBuffers(1, &id)
}
for i in 1 ..< MAX_PIPELINES {
if g_gl.pipelines[i].active {
destroy_graphics_pipeline_opengl(bk.Pipeline_Handle(i))
}
}
for i in 1 ..< MAX_SHADERS {
if g_gl.shaders[i].active {
destroy_shader_opengl(bk.Shader_Handle(i))
}
}
for i in 1 ..< MAX_BUFFERS {
if g_gl.buffers[i].active {
destroy_buffer_opengl(bk.Buffer_Handle(i))
}
}
for i in 1 ..< MAX_TEXTURES {
if g_gl.textures[i].active {
destroy_texture_opengl(bk.Texture_Handle(i))
}
}
for i in 1 ..< MAX_FRAMEBUFFERS {
if g_gl.framebuffers[i].active {
destroy_framebuffer_opengl(bk.Framebuffer_Handle(i))
}
}
for i in 1 ..< MAX_SAMPLERS {
if g_gl.samplers[i].active {
destroy_sampler_opengl(bk.Sampler_Handle(i))
}
}
destroy_gl_context(&g_gl.gl_ctx)
free(g_gl)
g_gl = nil
bk.backend_initialized = false
}
wait_idle_opengl :: proc() {
gl.Finish()
}
current_frame_index_opengl :: proc() -> u32 {
if g_gl == nil do return 0
return g_gl.current_frame
}
get_extent_opengl :: proc() -> bk.Extent {
if g_gl == nil do return {}
return {g_gl.width, g_gl.height}
}
on_resize_opengl :: proc(width, height: u32) {
if g_gl == nil do return
g_gl.width = width
g_gl.height = height
resize_gl_context(&g_gl.gl_ctx, width, height)
}
get_default_render_pass_opengl :: proc() -> bk.Render_Pass_Handle {
if g_gl == nil do return bk.NULL_RENDER_PASS
return g_gl.default_render_pass
}
get_depth_format_opengl :: proc() -> bk.Format {
return .D32_SFLOAT
}