use uint16_t for element array buffer data

this matches the use in the tinygltf library

src/asset.h

@@ -58,13 +58,13 @@ struct mesh
 {
 	GLenum draw_mode; // NOTE: GL_LINES, GL_TRIANGLES
 	GLenum usage; // NOTE: GL_STATIC_DRAW, GL_DYNAMIC_DRAW
-	uint num_vertices;
-	uint num_indices;
+	u32 num_vertices;
+	u32 num_indices;
 	glm::vec3* vertices;
 	glm::vec3* normals;
 	glm::vec2* uvs;
 	glm::vec3* colors;
-	uint* indices;
+	u16* indices;
 	glm::mat4* xform;
 };
 

src/main.cpp

@@ -55,8 +55,8 @@ initCubeMesh()
 	m.vertices[7] = {  1,  1,  1 };
 
 	m.num_indices = 36; // 6 sides, 2 tris per side, 3 verts per tri
-	m.indices = (u32*) std::calloc(m.num_indices, sizeof(u32));
-	u32 indices[36] = {
+	m.indices = (u16*) std::calloc(m.num_indices, sizeof(u16));
+	u16 indices[36] = {
 		0, 1, 2, 0, 2, 3,
 		3, 2, 6, 3, 6, 7,
 		7, 6, 5, 7, 5, 4,
@@ -64,7 +64,7 @@ initCubeMesh()
 		0, 3, 4, 0, 3, 7,
 		1, 2, 5, 2, 6, 5
 	};
-	std::memcpy(m.indices, indices, m.num_indices * sizeof(u32));
+	std::memcpy(m.indices, indices, m.num_indices * sizeof(u16));
 
 	return m;
 }

src/shader.cpp

@@ -117,7 +117,7 @@ renderVAO(GLmesh* glmesh)
 		(float*) glmesh->model_xform);
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, glmesh->idx_buf_id);
 	glDrawElements(
-		glmesh->draw_mode, glmesh->num_indices, GL_UNSIGNED_INT, 0);
+		glmesh->draw_mode, glmesh->num_indices, GL_UNSIGNED_SHORT, 0);
 	glBindVertexArray(0);
 }
 
@@ -379,7 +379,7 @@ loadGLMesh(shader_program* s,
 	glGenBuffers(1, &gm.idx_buf_id);
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gm.idx_buf_id);
 	glBufferData(GL_ELEMENT_ARRAY_BUFFER,
-		m.num_indices * sizeof(GLuint),
+		m.num_indices * sizeof(u16),
 		m.indices,
 		GL_STATIC_DRAW);
 

src/types.h

@@ -3,6 +3,7 @@
 
 typedef uint8_t u8;
 typedef int32_t i32;
+typedef uint16_t u16;
 typedef uint32_t u32;
 typedef uint64_t u64;