Gawain: remove GL enum from vertex format API

Callers now have to use Gawain's COMP enum to specify vertex attributes.

This makes the API more bullet-proof (at least less vulnerable) since GLenum covers waaay more than component types.

Also prepares us for Vulkan.

intern/gawain/gawain/vertex_format.h

@@ -22,17 +22,17 @@
 //   ^-- this is only guaranteed on Windows right now, will be true on all platforms soon
 
 typedef enum {
-	COMP_I8 = GL_BYTE,
+	COMP_I8,
-	COMP_U8 = GL_UNSIGNED_BYTE,
+	COMP_U8,
-	COMP_I16 = GL_SHORT,
+	COMP_I16,
-	COMP_U16 = GL_UNSIGNED_SHORT,
+	COMP_U16,
-	COMP_I32 = GL_INT,
+	COMP_I32,
-	COMP_U32 = GL_UNSIGNED_INT,
+	COMP_U32,
 
-	COMP_F32 = GL_FLOAT, // TODO: drop the GL_ equivalence here, use a private lookup table
+	COMP_F32,
 
 #if USE_10_10_10
-	COMP_I10 = GL_INT_2_10_10_10_REV
+	COMP_I10
 #endif
 } VertexCompType;
 
@@ -45,6 +45,7 @@ typedef enum {
 
 typedef struct {
 	VertexCompType comp_type;
+	unsigned gl_comp_type;
 	unsigned comp_ct; // 1 to 4
 	unsigned sz; // size in bytes, 1 to 16
 	unsigned offset; // from beginning of vertex, in bytes

intern/gawain/src/batch.c

@@ -137,13 +137,13 @@ static void Batch_update_program_bindings(Batch* batch)
 				{
 				case KEEP_FLOAT:
 				case CONVERT_INT_TO_FLOAT:
-					glVertexAttribPointer(loc, a->comp_ct, a->comp_type, GL_FALSE, stride, pointer);
+					glVertexAttribPointer(loc, a->comp_ct, a->gl_comp_type, GL_FALSE, stride, pointer);
 					break;
 				case NORMALIZE_INT_TO_FLOAT:
-					glVertexAttribPointer(loc, a->comp_ct, a->comp_type, GL_TRUE, stride, pointer);
+					glVertexAttribPointer(loc, a->comp_ct, a->gl_comp_type, GL_TRUE, stride, pointer);
 					break;
 				case KEEP_INT:
-					glVertexAttribIPointer(loc, a->comp_ct, a->comp_type, stride, pointer);
+					glVertexAttribIPointer(loc, a->comp_ct, a->gl_comp_type, stride, pointer);
 				}
 			}
 		}

intern/gawain/src/immediate.c

@@ -329,13 +329,13 @@ static void immDrawSetup(void)
 			{
 			case KEEP_FLOAT:
 			case CONVERT_INT_TO_FLOAT:
-				glVertexAttribPointer(loc, a->comp_ct, a->comp_type, GL_FALSE, stride, pointer);
+				glVertexAttribPointer(loc, a->comp_ct, a->gl_comp_type, GL_FALSE, stride, pointer);
 				break;
 			case NORMALIZE_INT_TO_FLOAT:
-				glVertexAttribPointer(loc, a->comp_ct, a->comp_type, GL_TRUE, stride, pointer);
+				glVertexAttribPointer(loc, a->comp_ct, a->gl_comp_type, GL_TRUE, stride, pointer);
 				break;
 			case KEEP_INT:
-				glVertexAttribIPointer(loc, a->comp_ct, a->comp_type, stride, pointer);
+				glVertexAttribIPointer(loc, a->comp_ct, a->gl_comp_type, stride, pointer);
 			}
 		}
 

intern/gawain/src/vertex_format.c

@@ -36,14 +36,33 @@ void VertexFormat_copy(VertexFormat* dest, const VertexFormat* src)
 	memcpy(dest, src, sizeof(VertexFormat));
 	}
 
+static GLenum convert_comp_type_to_gl(VertexCompType type)
+	{
+	static const GLenum table[] = {
+		[COMP_I8] = GL_BYTE,
+		[COMP_U8] = GL_UNSIGNED_BYTE,
+		[COMP_I16] = GL_SHORT,
+		[COMP_U16] = GL_UNSIGNED_SHORT,
+		[COMP_I32] = GL_INT,
+		[COMP_U32] = GL_UNSIGNED_INT,
+
+		[COMP_F32] = GL_FLOAT,
+
+	#if USE_10_10_10
+		[COMP_I10] = GL_INT_2_10_10_10_REV
+	#endif
+		};
+	return table[type];
+	}
+
 static unsigned comp_sz(VertexCompType type)
 	{
 #if TRUST_NO_ONE
-	assert(type >= GL_BYTE && type <= GL_FLOAT);
+	assert(type <= COMP_F32); // other types have irregular sizes (not bytes)
 #endif
 
 	const GLubyte sizes[] = {1,1,2,2,4,4,4};
-	return sizes[type - GL_BYTE];
+	return sizes[type];
 	}
 
 static unsigned attrib_sz(const Attrib *a)
@@ -137,6 +156,7 @@ unsigned VertexFormat_add_attrib(VertexFormat* format, const char* name, VertexC
 
 	attrib->name = copy_attrib_name(format, name);
 	attrib->comp_type = comp_type;
+	attrib->gl_comp_type = convert_comp_type_to_gl(comp_type);
 #if USE_10_10_10
 	attrib->comp_ct = (comp_type == COMP_I10) ? 4 : comp_ct; // system needs 10_10_10_2 to be 4 or BGRA
 #else