Optional vertex modulation in draw API

docs/api_reference.md

@@ -348,6 +348,7 @@ This is a list of all functions in Cute Framework organized by categories. This
 - [cf_draw_quad2](/draw/cf_draw_quad2.md)
 - [cf_draw_quad_fill](/draw/cf_draw_quad_fill.md)
 - [cf_draw_quad_fill2](/draw/cf_draw_quad_fill2.md)
+- [cf_draw_set_vertex_callback](/draw/cf_draw_set_vertex_callback.md)
 - [cf_draw_sprite](/draw/cf_draw_sprite.md)
 - [cf_draw_tri](/draw/cf_draw_tri.md)
 - [cf_draw_tri_fill](/draw/cf_draw_tri_fill.md)
@@ -373,10 +374,12 @@ This is a list of all functions in Cute Framework organized by categories. This
 - [cf_render_settings_push_viewport](/draw/cf_render_settings_push_viewport.md)
 - [cf_render_settings_set_atlas_dimensions](/draw/cf_render_settings_set_atlas_dimensions.md)
 - [cf_render_to](/draw/cf_render_to.md)
+- [CF_VertexFn](/draw/cf_vertexfn.md)
 
 
 ### structs
 - [CF_TemporaryImage](/draw/cf_temporaryimage.md)
+- [CF_Vertex](/draw/cf_vertex.md)
 
 
 ## graphics

docs/draw/cf_draw_set_vertex_callback.md

@@ -0,0 +1,34 @@
+[](../header.md ':include')
+
+# cf_draw_set_vertex_callback
+
+Category: [draw](/api_reference?id=draw)  
+GitHub: [cute_draw.h](https://github.com/RandyGaul/cute_framework/blob/master/include/cute_draw.h)  
+---
+
+An optional callback for modifying vertices before they are sent to the GPU.
+
+```cpp
+void cf_draw_set_vertex_callback(CF_VertexFn* vertex_fn);
+```
+
+## Remarks
+
+Setup this callback to apply per-vertex modulations for implementing advanced graphical effects.
+`Count` is always a multiple of three, as this function always processes large batched arrays of
+triangles. Since all shapes are rendered with signed-distance functions, most shapes merely generate
+a single quad, so you may find triangle counts lower than originally anticipated.
+
+Call [cf_draw_set_vertex_callback](/draw/cf_draw_set_vertex_callback.md) to setup your callback.
+
+There is no adjecancy info provided. If you need to know which triangles connect to others you
+should probably redesign your feature to not require adjecancy information, or use your own custom
+rendering solution. With a custom solution you may use low-level graphics in cute_graphics.h, where
+any adjacency info can be controlled 100% by you a-priori.
+
+## Related Pages
+
+[CF_Vertex](/draw/cf_vertex.md)  
+[CF_VertexFn](/draw/cf_vertexfn.md)  
+cf_draw_push_vertex_callback  
+cf_draw_pop_vertex_callback  

docs/draw/cf_vertex.md

@@ -0,0 +1,38 @@
+[](../header.md ':include')
+
+# CF_Vertex
+
+Category: [draw](/api_reference?id=draw)  
+GitHub: [cute_draw.h](https://github.com/RandyGaul/cute_framework/blob/master/include/cute_draw.h)  
+---
+
+The full vertex layout CF uses just before sending verts to the GPU.
+
+Struct Members | Description
+--- | ---
+`CF_V2 p` | World space position.
+`CF_V2 posH` | "Homogenous" position transformed by the camera.
+`CF_V2 a, b, c` | For internal use -- used in signed-distance functions for rendering shapes.
+`CF_V2 uv` | For internal use -- used for sprite rendering.
+`CF_Pixel color` | Color for rendering shapes (ignored for sprites).
+`float radius` | For internal use -- Used for applying "chubbiness" factor for shapes, or radii on circle/capsule.
+`float stroke` | For internal use -- Used for shape rendering for border style stroke rendering (no fill).
+`float aa` | For internal use -- Factor for the size of antialiasing.
+`uint8_t type` | For internal use -- The type of shape to be rendered, used by the signed-distance functions within CF's internal fragment shader.
+`uint8_t alpha` | Used for the alpha-component (transparency).
+`uint8_t fill` | For internal use -- Whether or not to render shapes as filled or strokedx.
+`uint8_t not_used` | For internal use -- Reserved for a future purpose, simply fulfills byte alignment for now.
+`CF_Color attributes` | Four general purpose floats passed into custom user shaders.
+
+## Remarks
+
+You may fill in vertices via callback by `cf_draw_push_vertex_callback`. See [CF_VertexFn](/draw/cf_vertexfn.md).
+This is useful when you need to fill in unique `attributes` per-vertex, or modify any other
+bits of the vertex before rendering. This could be used to implement features like dynamically
+generated UV's for shape slicing, or complex lighting systems.
+
+## Related Pages
+
+cf_draw_pop_vertex_callback  
+[CF_VertexFn](/draw/cf_vertexfn.md)  
+cf_draw_push_vertex_callback  

docs/draw/cf_vertexfn.md

@@ -0,0 +1,33 @@
+[](../header.md ':include')
+
+# CF_VertexFn
+
+Category: [draw](/api_reference?id=draw)  
+GitHub: [cute_draw.h](https://github.com/RandyGaul/cute_framework/blob/master/include/cute_draw.h)  
+---
+
+An optional callback for modifying vertices before they are sent to the GPU.
+
+```cpp
+typedef void (CF_VertexFn)(CF_Vertex* verts, int count);
+```
+
+## Remarks
+
+Setup this callback to apply per-vertex modulations for implementing advanced graphical effects.
+`Count` is always a multiple of three, as this function always processes large batched arrays of
+triangles. Since all shapes are rendered with signed-distance functions, most shapes merely generate
+a single quad, so you may find triangle counts lower than originally anticipated.
+
+Call [cf_draw_set_vertex_callback](/draw/cf_draw_set_vertex_callback.md) to setup your callback.
+
+There is no adjecancy info provided. If you need to know which triangles connect to others you
+should probably redesign your feature to not require adjecancy information, or use your own custom
+rendering solution. With a custom solution you may use low-level graphics in cute_graphics.h, where
+any adjacency info can be controlled 100% by you a-priori.
+
+## Related Pages
+
+[CF_Vertex](/draw/cf_vertex.md)  
+cf_draw_pop_vertex_callback  
+cf_draw_push_vertex_callback  

include/cute_draw.h

@@ -503,6 +503,97 @@ CF_API CF_Color CF_CALL cf_draw_pop_vertex_attributes();
  */
 CF_API CF_Color CF_CALL cf_draw_peek_vertex_attributes();
 
+/**
+ * @struct   CF_Vertex
+ * @category draw
+ * @brief    The full vertex layout CF uses just before sending verts to the GPU.
+ * @remarks  You may fill in vertices via callback by `cf_draw_push_vertex_callback`. See `CF_VertexFn`.
+ *           This is useful when you need to fill in unique `attributes` per-vertex, or modify any other
+ *           bits of the vertex before rendering. This could be used to implement features like dynamically
+ *           generated UV's for shape slicing, or complex lighting systems.
+ * @related  CF_Vertex CF_VertexFn cf_draw_push_vertex_callback cf_draw_pop_vertex_callback
+ */
+typedef struct CF_Vertex
+{
+	/* @member World space position. */
+	CF_V2 p;
+
+	/* @member "Homogenous" position transformed by the camera. */
+	CF_V2 posH;
+
+	/* @member For internal use -- used in signed-distance functions for rendering shapes. */
+	CF_V2 a, b, c;
+
+	/* @member For internal use -- used for sprite rendering. */
+	CF_V2 uv;
+
+	/* @member Color for rendering shapes (ignored for sprites). */
+	CF_Pixel color;
+
+	/* @member For internal use -- Used for applying "chubbiness" factor for shapes, or radii on circle/capsule. */
+	float radius;
+
+	/* @member For internal use -- Used for shape rendering for border style stroke rendering (no fill). */
+	float stroke;
+
+	/* @member For internal use -- Factor for the size of antialiasing. */
+	float aa;
+
+	/* @member For internal use -- The type of shape to be rendered, used by the signed-distance functions within CF's internal fragment shader. */
+	uint8_t type;
+
+	/* @member Used for the alpha-component (transparency). */
+	uint8_t alpha;
+
+	/* @member For internal use -- Whether or not to render shapes as filled or strokedx. */
+	uint8_t fill;
+
+	/* @member For internal use -- Reserved for a future purpose, simply fulfills byte alignment for now. */
+	uint8_t not_used;
+
+	/* @member Four general purpose floats passed into custom user shaders. */
+	CF_Color attributes;
+} CF_Vertex;
+// @end
+
+/**
+ * @function CF_VertexFn
+ * @category draw
+ * @brief    An optional callback for modifying vertices before they are sent to the GPU.
+ * @remarks  Setup this callback to apply per-vertex modulations for implementing advanced graphical effects.
+ *           `Count` is always a multiple of three, as this function always processes large batched arrays of
+ *           triangles. Since all shapes are rendered with signed-distance functions, most shapes merely generate
+ *           a single quad, so you may find triangle counts lower than originally anticipated.
+ *           
+ *           Call `cf_draw_set_vertex_callback` to setup your callback.
+ *           
+ *           There is no adjecancy info provided. If you need to know which triangles connect to others you
+ *           should probably redesign your feature to not require adjecancy information, or use your own custom
+ *           rendering solution. With a custom solution you may use low-level graphics in cute_graphics.h, where
+ *           any adjacency info can be controlled 100% by you a-priori.
+ * @related  CF_Vertex CF_VertexFn cf_draw_push_vertex_callback cf_draw_pop_vertex_callback
+ */
+typedef void (CF_VertexFn)(CF_Vertex* verts, int count);
+
+/**
+ * @function cf_draw_set_vertex_callback
+ * @category draw
+ * @brief    An optional callback for modifying vertices before they are sent to the GPU.
+ * @remarks  Setup this callback to apply per-vertex modulations for implementing advanced graphical effects.
+ *           `Count` is always a multiple of three, as this function always processes large batched arrays of
+ *           triangles. Since all shapes are rendered with signed-distance functions, most shapes merely generate
+ *           a single quad, so you may find triangle counts lower than originally anticipated.
+ *           
+ *           Call `cf_draw_set_vertex_callback` to setup your callback.
+ *           
+ *           There is no adjecancy info provided. If you need to know which triangles connect to others you
+ *           should probably redesign your feature to not require adjecancy information, or use your own custom
+ *           rendering solution. With a custom solution you may use low-level graphics in cute_graphics.h, where
+ *           any adjacency info can be controlled 100% by you a-priori.
+ * @related  CF_Vertex CF_VertexFn cf_draw_push_vertex_callback cf_draw_pop_vertex_callback
+ */
+CF_API void CF_CALL cf_draw_set_vertex_callback(CF_VertexFn* vertex_fn);
+
 /**
  * @function cf_make_font
  * @category text