Updated C API, made it easier to port GPUDriver-related structs to ot…

…her languages by limiting custom byte alignment to vertex declarations.

Ultralight/CAPI.h

@@ -1481,12 +1481,6 @@ typedef struct {
  * GPUDriver
  *****************************************************************************/
 
-///
-/// @note  This pragma pack(push, 1) command is important! Vertex layouts
-///	       should not be padded with any bytes.
-///
-#pragma pack(push, 1)
-
 ///
 /// Render buffer description.
 ///
@@ -1498,9 +1492,17 @@ typedef struct {
   bool has_depth_buffer;    // Currently unsued, always false.
 } ULRenderBuffer;
 
+///
+/// @note  This pragma pack(push, 1) command is important! Vertex layouts
+///	       should not be padded with any bytes.
+///
+#pragma pack(push, 1)
+
 ///
 /// Vertex layout for path vertices.
 ///
+/// (this struct's members aligned on single-byte boundaries)
+///
 typedef struct {
   float pos[2];
   unsigned char color[4];
@@ -1510,6 +1512,8 @@ typedef struct {
 ///
 /// Vertex layout for quad vertices.
 ///
+/// (this struct's members aligned on single-byte boundaries)
+///
 typedef struct {
   float pos[2];
   unsigned char color[4];
@@ -1524,6 +1528,11 @@ typedef struct {
   float data6[4];
 } ULVertex_2f_4ub_2f_2f_28f;
 
+///
+/// End single-byte alignment.
+///
+#pragma pack(pop)
+
 ///
 /// Vertex formats.
 ///
@@ -1621,7 +1630,7 @@ typedef struct {
   /// The following four members are passed to the pixel shader via uniforms.
   float uniform_scalar[8];
   ULvec4 uniform_vector[8];
-  unsigned int clip_size;
+  unsigned char clip_size;
   ULMatrix4x4 clip[8];
 
   /// Whether or not scissor testing should be used for the current draw
@@ -1660,8 +1669,6 @@ typedef struct {
   ULCommand* commands;
 } ULCommandList;
 
-#pragma pack(pop)
-
 ///
 /// The callback invoked when the GPUDriver will begin dispatching commands
 /// (such as CreateTexture and UpdateCommandList) during the current call to