9 files changed, 405 insertions, 0 deletions
diff --git a/src/ral/README.md b/src/ral/README.md
new file mode 100644
index 0000000..f66b95a
--- /dev/null
+++ b/src/ral/README.md
@@ -0,0 +1,5 @@
+# RAL
+
+**Render Abstraction Layer** is a thin abstraction over graphics APIs. Everything in `render` builds on top of the code in
+this folder in order to be API-agnostic. It also makes writing graphics code easier as it smooths over some of the discrepancies
+between APIs like texture/buffer creation and updating shader values.
+\ No newline at end of file
diff --git a/src/ral/backends/metal/backend_metal.h b/src/ral/backends/metal/backend_metal.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/ral/backends/metal/backend_metal.h
diff --git a/src/ral/backends/opengl/backend_opengl.h b/src/ral/backends/opengl/backend_opengl.h
new file mode 100644
index 0000000..22162f3
--- /dev/null
+++ b/src/ral/backends/opengl/backend_opengl.h
@@ -0,0 +1,76 @@
+#pragma once
+
+#include "ral_impl.h"
+#ifdef CEL_REND_BACKEND_OPENGL
+
+#include "defines.h"
+#include "maths_types.h"
+#include "ral.h"
+#include "ral_types.h"
+
+#define MAX_PIPELINE_UNIFORM_BUFFERS 32
+
+#define OPENGL_DEFAULT_FRAMEBUFFER 0
+
+typedef struct GPU_Swapchain{
+  u32x2 dimensions;
+}GPU_Swapchain;
+
+typedef struct GPU_Device {
+} GPU_Device;
+
+typedef struct GPU_PipelineLayout{
+  void *pad;
+}GPU_PipelineLayout;
+
+typedef struct GPU_Pipeline {
+  u32 shader_id;
+  GPU_Renderpass* renderpass;
+  VertexDescription vertex_desc;
+  BufferHandle uniform_bindings[MAX_PIPELINE_UNIFORM_BUFFERS];
+  u32 uniform_count;
+  bool wireframe;
+} GPU_Pipeline;
+
+typedef struct GPU_Renderpass {
+  u32 fbo;
+  GPU_RenderpassDesc description;
+} GPU_Renderpass;
+
+typedef struct GPU_CmdEncoder {
+  GPU_Pipeline *pipeline;
+} GPU_CmdEncoder;  // Recording
+
+typedef struct gpu_cmd_buffer {
+  void *pad;
+} gpu_cmd_buffer;  // Ready for submission
+
+typedef struct GPU_Buffer {
+  union {
+    u32 vbo;
+    u32 ibo;
+    u32 ubo;
+  } id;
+  union {
+    u32 vao;
+    u32 ubo_binding_point
+  }; // Optional
+  char* name;
+  u64 size;
+} GPU_Buffer;
+
+typedef struct GPU_Texture {
+  u32 id;
+  void* pad;
+} GPU_Texture;
+
+typedef struct opengl_support {
+} opengl_support;
+
+u32 shader_create_separate(const char *vert_shader, const char *frag_shader);
+
+void uniform_vec3f(u32 program_id, const char *uniform_name, Vec3 *value);
+void uniform_f32(u32 program_id, const char *uniform_name, f32 value);
+void uniform_i32(u32 program_id, const char *uniform_name, i32 value);
+void uniform_mat4f(u32 program_id, const char *uniform_name, Mat4 *value);
+#endif
diff --git a/src/ral/backends/vulkan/backend_vulkan.h b/src/ral/backends/vulkan/backend_vulkan.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/ral/backends/vulkan/backend_vulkan.h
diff --git a/src/ral/ral.h b/src/ral/ral.h
new file mode 100644
index 0000000..ce3b27d
--- /dev/null
+++ b/src/ral/ral.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#include "ral_types.h"
+#include "ral_common.h"
+#include "ral_impl.h"
+\ No newline at end of file
diff --git a/src/ral/ral_common.c b/src/ral/ral_common.c
new file mode 100644
index 0000000..89d475b
--- /dev/null
+++ b/src/ral/ral_common.c
@@ -0,0 +1,19 @@
+#include "ral_common.h"
+#include "ral_impl.h"
+
+void backend_pools_init(arena* a, GPU_BackendPools* backend_pools) {
+  PipelineLayout_pool pipeline_layout_pool =
+      PipelineLayout_pool_create(a, MAX_PIPELINES, sizeof(GPU_PipelineLayout));
+  backend_pools->pipeline_layouts = pipeline_layout_pool;
+  Pipeline_pool pipeline_pool = Pipeline_pool_create(a, MAX_PIPELINES, sizeof(GPU_Pipeline));
+  backend_pools->pipelines = pipeline_pool;
+  Renderpass_pool rpass_pool = Renderpass_pool_create(a, MAX_RENDERPASSES, sizeof(GPU_Renderpass));
+  backend_pools->renderpasses = rpass_pool;
+}
+
+void resource_pools_init(arena* a, struct ResourcePools* res_pools) {
+  Buffer_pool buf_pool = Buffer_pool_create(a, MAX_BUFFERS, sizeof(GPU_Buffer));
+  res_pools->buffers = buf_pool;
+  Texture_pool tex_pool = Texture_pool_create(a, MAX_TEXTURES, sizeof(GPU_Texture));
+  res_pools->textures = tex_pool;
+}
diff --git a/src/ral/ral_common.h b/src/ral/ral_common.h
new file mode 100644
index 0000000..1088404
--- /dev/null
+++ b/src/ral/ral_common.h
@@ -0,0 +1,39 @@
+#pragma once
+#include "defines.h"
+#include "buf.h"
+#include "mem.h"
+#include "ral_types.h"
+#include "ral_impl.h"
+
+
+TYPED_POOL(GPU_Buffer, Buffer);
+TYPED_POOL(GPU_Texture, Texture);
+TYPED_POOL(GPU_PipelineLayout, PipelineLayout);
+TYPED_POOL(GPU_Pipeline, Pipeline);
+TYPED_POOL(GPU_Renderpass, Renderpass);
+
+// --- Handy macros
+#define BUFFER_GET(h) (buffer_pool_get(&context.resource_pools->buffers, h))
+#define TEXTURE_GET(h) (texture_pool_get(&context.resource_pools->textures, h))
+
+// --- Pools
+typedef struct GPU_BackendPools{
+  Pipeline_pool pipelines;
+  PipelineLayout_pool pipeline_layouts;
+  Renderpass_pool renderpasses;
+} GPU_BackendPools;
+void backend_pools_init(arena* a, GPU_BackendPools* backend_pools);
+
+struct ResourcePools {
+  Buffer_pool buffers;
+  Texture_pool textures;
+};
+void resource_pools_init(arena* a, struct ResourcePools* res_pools);
+
+
+// --- Vertex formats
+bytebuffer vertices_as_bytebuffer(arena* a, VertexFormat format, Vertex_darray* vertices);
+
+void vertex_desc_add(VertexDescription* builder, const char* name, VertexAttribType type);
+VertexDescription static_3d_vertex_description();
+size_t vertex_attrib_size(VertexAttribType attr);
diff --git a/src/ral/ral_impl.h b/src/ral/ral_impl.h
new file mode 100644
index 0000000..4d1c17a
--- /dev/null
+++ b/src/ral/ral_impl.h
@@ -0,0 +1,38 @@
+/**
+ * @brief
+*/
+#pragma once
+#include "defines.h"
+#include "ral_types.h"
+
+struct GLFWwindow;
+
+// Forward declare structs - these must be defined in the backend implementation
+typedef struct GPU_Swapchain GPU_Swapchain;
+typedef struct GPU_Device GPU_Device;
+typedef struct GPU_PipelineLayout GPU_PipelineLayout;
+typedef struct GPU_Pipeline GPU_Pipeline;
+typedef struct GPU_Renderpass GPU_Renderpass;
+typedef struct GPU_CmdEncoder GPU_CmdEncoder;  // Recording
+typedef struct GPU_CmdBuffer GPU_CmdBuffer;    // Ready for submission
+typedef struct GPU_Buffer GPU_Buffer;
+typedef struct GPU_Texture GPU_Texture;
+
+bool GPU_Backend_Init(const char* window_name, struct GLFWwindow* window);
+void GPU_Backend_Shutdown();
+
+bool GPU_Device_Create(GPU_Device* out_device);
+void GPU_Device_Destroy(GPU_Device* device);
+
+bool GPU_Swapchain_Create(GPU_Swapchain* out_swapchain);
+void GPU_Swapchain_Destroy(GPU_Swapchain* swapchain);
+
+GPU_Renderpass* GPU_Renderpass_Create(GPU_RenderpassDesc description);
+void GPU_Renderpass_Destroy(GPU_Renderpass* pass);
+
+GPU_Pipeline* GPU_GraphicsPipeline_Create(GraphicsPipelineDesc description, GPU_Renderpass* renderpass);
+void GraphicsPipeline_Destroy(GPU_Pipeline* pipeline);
+
+#if defined(CEL_REND_BACKEND_OPENGL)
+#include "backend_opengl.h"
+#endif
diff --git a/src/ral/ral_types.h b/src/ral/ral_types.h
new file mode 100644
index 0000000..0ba7f87
--- /dev/null
+++ b/src/ral/ral_types.h
@@ -0,0 +1,223 @@
+#pragma once
+#include "defines.h"
+#include "darray.h"
+#include "maths_types.h"
+
+// --- Max size constants
+#define MAX_SHADER_DATA_LAYOUTS 8
+#define MAX_SHADER_BINDINGS 8
+#define MAX_BUFFERS 256
+#define MAX_TEXTURES 256
+#define MAX_PIPELINES 128
+#define MAX_RENDERPASSES 128
+#define MAX_VERTEX_ATTRIBUTES 16
+
+// --- Handle types
+CORE_DEFINE_HANDLE(BufferHandle);
+CORE_DEFINE_HANDLE(TextureHandle);
+CORE_DEFINE_HANDLE(SamplerHandle);
+CORE_DEFINE_HANDLE(ShaderHandle);
+CORE_DEFINE_HANDLE(PipelineLayoutHandle);
+CORE_DEFINE_HANDLE(PipelineHandle);
+CORE_DEFINE_HANDLE(RenderpassHandle);
+
+// --- Buffers
+typedef enum GPU_BufferType{
+  BUFFER_DEFAULT,  // on Vulkan this would be a storage buffer?
+  BUFFER_VERTEX,
+  BUFFER_INDEX,
+  BUFFER_UNIFORM,
+  BUFFER_COUNT
+} GPU_BufferType;
+
+static const char* buffer_type_names[] = {
+  "RAL Buffer Default", "RAL Buffer Vertex", "RAL Buffer Index",
+  "RAL Buffer Uniform", "RAL Buffer Count",
+};
+
+typedef enum GPU_BufferFlag {
+  BUFFER_FLAG_CPU = 1 << 0,
+  BUFFER_FLAG_GPU = 1 << 1,
+  BUFFER_FLAG_STORAGE = 1 << 2,
+  BUFFER_FLAG_COUNT
+} GPU_BufferFlag;
+typedef u32 GPU_BufferFlags;
+
+// --- Textures
+typedef enum GPU_TextureType {
+  TEXTURE_TYPE_2D,
+  TEXTURE_TYPE_3D,
+  TEXTURE_TYPE_2D_ARRAY,
+  TEXTURE_TYPE_CUBE_MAP,
+  TEXTURE_TYPE_COUNT
+} GPU_TextureType;
+
+typedef enum GPU_TextureFormat {
+  TEXTURE_FORMAT_8_8_8_8_RGBA_UNORM,
+  TEXTURE_FORMAT_DEPTH_DEFAULT,
+  TEXTURE_FORMAT_COUNT
+} GPU_TextureFormat;
+
+/** @brief Texture Description - used by texture creation functions */
+typedef struct TextureDesc {
+  GPU_TextureType tex_type;
+  GPU_TextureFormat format;
+  u32x2 extents;
+} TextureDesc;
+
+// --- Vertices
+
+typedef enum VertexFormat {
+  VERTEX_STATIC_3D,
+  VERTEX_SPRITE,
+  VERTEX_SKINNED,
+  VERTEX_COLOURED_STATIC_3D,
+  VERTEX_RAW_POS_COLOUR,
+  VERTEX_COUNT
+} VertexFormat;
+
+typedef union Vertex {
+  struct {
+    Vec3 position;
+    Vec3 normal;
+    Vec2 tex_coords;
+  } static_3d; /** @brief standard vertex format for static geometry in 3D */
+
+  struct {
+    Vec2 position;
+    Vec4 colour;
+    Vec2 tex_coords;
+  } sprite; /** @brief vertex format for 2D sprites or quads */
+
+  struct {
+    Vec3 position;
+    Vec4 colour;
+    Vec2 tex_coords;
+    Vec3 normal;
+    Vec4i bone_ids;     // Integer vector for bone IDs
+    Vec4 bone_weights;  // Weight of each bone's influence
+  } skinned_3d;         /** @brief vertex format for skeletal (animated) geometry in 3D */
+
+  struct {
+    Vec3 position;
+    Vec2 tex_coords;
+    Vec3 normal;
+    Vec4 colour;
+  } coloured_static_3d; /** @brief vertex format used for debugging */
+
+  struct {
+    Vec2 position;
+    Vec3 colour;
+  } raw_pos_colour;
+} Vertex;
+
+#ifndef TYPED_VERTEX_ARRAY
+KITC_DECL_TYPED_ARRAY(Vertex);
+KITC_DECL_TYPED_ARRAY(u32)
+#define TYPED_VERTEX_ARRAY
+#endif
+
+/// @strip_prefix(ATTR_)
+typedef enum VertexAttribType {
+  ATTR_F32,
+  ATTR_F32x2,
+  ATTR_F32x3,
+  ATTR_F32x4,
+  ATTR_U32,
+  ATTR_U32x2,
+  ATTR_U32x3,
+  ATTR_U32x4,
+  ATTR_I32,
+  ATTR_I32x2,
+  ATTR_I32x3,
+  ATTR_I32x4,
+} VertexAttribType;
+
+typedef struct VertexDescription {
+    char* debug_label;
+    const char* attr_names[MAX_VERTEX_ATTRIBUTES];
+    VertexAttribType attributes[MAX_VERTEX_ATTRIBUTES];
+    u32 attributes_count;
+    size_t stride;
+    bool use_full_vertex_size;
+} VertexDescription;
+
+// --- Shaders
+typedef enum ShaderVisibility {
+    VISIBILITY_VERTEX = 1 << 0,
+    VISIBILITY_FRAGMENT = 1 << 1,
+    VISIBILITY_COMPUTE = 1 << 2,
+} ShaderVisibility ;
+
+typedef struct ShaderDesc {} ShaderDesc;
+
+typedef enum ShaderBindingKind {
+    BINDING_BUFFER,
+    BINDING_BUFFER_ARRAY,
+    BINDING_TEXTURE,
+    BINDING_TEXTURE_ARRAY,
+    // TODO: sampler
+    BINDING_COUNT
+} ShaderBindingKind;
+
+typedef struct ShaderBinding {
+    const char* label;
+    ShaderBindingKind kind;
+    ShaderVisibility vis;
+    union {
+        struct { u32 size; } bytes;
+        struct { BufferHandle handle; } buffer;
+        struct { TextureHandle handle; } texture;
+    } data;
+} ShaderBinding;
+
+typedef struct ShaderDataLayout {
+    ShaderBinding* bindings;
+    size_t binding_count;
+} ShaderDataLayout;
+
+typedef ShaderDataLayout (*FN_GetBindingLayout)(void);
+
+typedef struct ShaderData {
+    FN_GetBindingLayout get_layout;
+    void* data;
+} ShaderData;
+
+// --- Miscellaneous
+
+typedef enum PrimitiveTopology {
+  PRIMITIVE_TOPOLOGY_POINT,
+  PRIMITIVE_TOPOLOGY_LINE,
+  PRIMITIVE_TOPOLOGY_LINE_STRIP,
+  PRIMITIVE_TOPOLOGY_TRIANGLE,
+  PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP,
+  PRIMITIVE_TOPOLOGY_COUNT
+} PrimitiveTopology;
+
+typedef enum CullMode { CULL_BACK_FACE, CULL_FRONT_FACE, CULL_COUNT } CullMode;
+
+typedef struct GraphicsPipelineDesc {
+    // GPU_Renderpass* renderpass -> takes a renderpass in the create function
+  const char* debug_name;
+  VertexDescription vertex_desc;
+  ShaderDesc vs; /** @brief Vertex shader stage */
+  ShaderDesc fs; /** @brief Fragment shader stage */
+
+  // Roughly equivalent to a descriptor set layout each. each layout can have multiple bindings
+  // examples:
+  // - uniform buffer reprensenting view projection matrix
+  // - texture for shadow map
+  ShaderData data_layouts[MAX_SHADER_DATA_LAYOUTS];
+  u32 data_layouts_count;
+
+  bool wireframe;
+  bool depth_test;
+} GraphicsPipelineDesc;
+
+typedef struct GPU_RenderpassDesc {
+  bool default_framebuffer;
+  bool has_color_target;
+  TextureHandle  color_target; // for now only support one
+  bool has_depth_stencil;
+  TextureHandle  depth_stencil;
+} GPU_RenderpassDesc;