major gfx refactor from fixed function to shader based

src/gfx/pxl8_shader.h

@@ -0,0 +1,81 @@
+#pragma once
+
+#include "pxl8_lights.h"
+#include "pxl8_math.h"
+#include "pxl8_types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct pxl8_vertex_in {
+    pxl8_vec3 a_position;
+    pxl8_vec3 a_normal;
+    pxl8_vec2 a_uv;
+    u8 a_color;
+    u8 a_light;
+} pxl8_vertex_in;
+
+typedef struct pxl8_vertex_out {
+    pxl8_vec4 gl_Position;
+    pxl8_vec2 v_uv;
+    pxl8_vec3 v_world;
+    pxl8_vec3 v_normal;
+    f32 v_light;
+    f32 v_depth;
+} pxl8_vertex_out;
+
+typedef struct pxl8_shader_uniforms {
+    u8 ambient;
+    bool baked_lighting;
+    pxl8_vec3 celestial_dir;
+    f32 celestial_intensity;
+    bool dither;
+    bool dynamic_lighting;
+    bool emissive;
+    u8 fog_color;
+    f32 fog_density;
+    const pxl8_light* lights;
+    u32 lights_count;
+    bool textures;
+    f32 time;
+} pxl8_shader_uniforms;
+
+typedef struct pxl8_shader_bindings {
+    const u8* colormap;
+    const u32* palette;
+    const u8* atlas;
+    u32 width, height;
+    bool use_tiled;
+    union {
+        struct {
+            u32 stride;
+            u32 x, y;
+        } linear;
+        struct {
+            u32 base;
+            u8 log2_w;
+        } tiled;
+    };
+} pxl8_shader_bindings;
+
+typedef struct pxl8_shader_ctx {
+    i32 x, y;
+    pxl8_vec2 v_uv;
+    pxl8_vec3 v_world;
+    pxl8_vec3 v_normal;
+    f32 v_color;
+    f32 v_light;
+    f32 v_depth;
+    u32 out_light_color;
+} pxl8_shader_ctx;
+
+typedef u8 (*pxl8_shader_fn)(
+    pxl8_shader_ctx* ctx,
+    const pxl8_shader_bindings* bindings,
+    const pxl8_shader_uniforms* uniforms
+);
+
+#ifdef __cplusplus
+}
+#endif