From efb45a6851563cdb8077b6aad3ab92d4006d8790 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 20 Mar 2021 13:44:09 +0200
Subject: [PATCH] Decouple DataType from the OpenGL constants

This allows defining the values so that manipulation of related types is
easier.  And I can't keep relying on the GL values anyway, with the goal
of adding a Vulkan backend.
---
 source/core/batch.cpp       |  6 ++++--
 source/core/batch.h         |  1 +
 source/core/datatype.cpp    | 21 +++++++++++----------
 source/core/datatype.h      | 22 ++++++++++++----------
 source/core/texture1d.cpp   |  4 ++--
 source/core/texture2d.cpp   |  4 ++--
 source/core/texture3d.cpp   |  4 ++--
 source/core/texturecube.cpp |  4 ++--
 8 files changed, 36 insertions(+), 30 deletions(-)

diff --git a/source/core/batch.cpp b/source/core/batch.cpp
index f14cc307..68e232ba 100644
--- a/source/core/batch.cpp
+++ b/source/core/batch.cpp
@@ -55,6 +55,7 @@ unsigned Batch::restart_index = 0;
 Batch::Batch(PrimitiveType t):
 	prim_type(t),
 	index_type(UNSIGNED_SHORT),
+	gl_index_type(get_gl_type(index_type)),
 	max_index(0),
 	restart(false)
 { }
@@ -76,6 +77,7 @@ void Batch::set_index_type(DataType t)
 		shrink<UInt32, UInt16>(data);
 
 	index_type = t;
+	gl_index_type = get_gl_type(t);
 	update_offset();
 	dirty = true;
 }
@@ -189,7 +191,7 @@ void Batch::draw() const
 	BindRestore _bind_ibuf(get_buffer(), ELEMENT_ARRAY_BUFFER);
 	const void *data_ptr = setup_draw();
 
-	glDrawElements(prim_type, size(), index_type, data_ptr);
+	glDrawElements(prim_type, size(), gl_index_type, data_ptr);
 }
 
 void Batch::draw_instanced(unsigned count) const
@@ -199,7 +201,7 @@ void Batch::draw_instanced(unsigned count) const
 	BindRestore _bind_ibuf(get_buffer(), ELEMENT_ARRAY_BUFFER);
 	const void *data_ptr = setup_draw();
 
-	glDrawElementsInstanced(prim_type, size(), index_type, data_ptr, count);
+	glDrawElementsInstanced(prim_type, size(), gl_index_type, data_ptr, count);
 }
 
 const void *Batch::setup_draw() const
diff --git a/source/core/batch.h b/source/core/batch.h
index 2e4ad9ef..0435feec 100644
--- a/source/core/batch.h
+++ b/source/core/batch.h
@@ -34,6 +34,7 @@ public:
 private:
 	PrimitiveType prim_type;
 	DataType index_type;
+	GLenum gl_index_type;
 	std::vector<UInt8> data;
 	unsigned max_index;
 	bool restart;
diff --git a/source/core/datatype.cpp b/source/core/datatype.cpp
index 1def3ca3..7488a68b 100644
--- a/source/core/datatype.cpp
+++ b/source/core/datatype.cpp
@@ -1,4 +1,5 @@
 #include <stdexcept>
+#include <msp/gl/extensions/nv_half_float.h>
 #include "datatype.h"
 
 using namespace std;
@@ -6,19 +7,19 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
-unsigned get_type_size(DataType type)
+GLenum get_gl_type(DataType type)
 {
 	switch(type)
 	{
-	case BYTE:
-	case UNSIGNED_BYTE: return 1;
-	case SHORT:
-	case UNSIGNED_SHORT:
-	case HALF_FLOAT: return 2;
-	case INT:
-	case UNSIGNED_INT:
-	case FLOAT: return 4;
-	default: throw invalid_argument("get_type_size");
+	case BYTE: return GL_BYTE;
+	case UNSIGNED_BYTE: return GL_UNSIGNED_BYTE;
+	case SHORT: return GL_SHORT;
+	case UNSIGNED_SHORT: return GL_UNSIGNED_SHORT;
+	case INT: return GL_INT;
+	case UNSIGNED_INT: return GL_UNSIGNED_INT;
+	case FLOAT: return GL_FLOAT;
+	case HALF_FLOAT: return GL_HALF_FLOAT;
+	default: throw invalid_argument("get_gl_type");
 	}
 }
 
diff --git a/source/core/datatype.h b/source/core/datatype.h
index 2d783f61..a343e8cf 100644
--- a/source/core/datatype.h
+++ b/source/core/datatype.h
@@ -2,24 +2,26 @@
 #define MSP_GL_DATATYPE_H_
 
 #include "gl.h"
-#include <msp/gl/extensions/nv_half_float.h>
 
 namespace Msp {
 namespace GL {
 
 enum DataType
 {
-	BYTE           = GL_BYTE,
-	UNSIGNED_BYTE  = GL_UNSIGNED_BYTE,
-	SHORT          = GL_SHORT,
-	UNSIGNED_SHORT = GL_UNSIGNED_SHORT,
-	INT            = GL_INT,
-	UNSIGNED_INT   = GL_UNSIGNED_INT,
-	FLOAT          = GL_FLOAT,
-	HALF_FLOAT     = GL_HALF_FLOAT
+	BYTE = 0x101,
+	UNSIGNED_BYTE = 0x001,
+	SHORT = 0x102,
+	UNSIGNED_SHORT = 0x002,
+	INT = 0x104,
+	UNSIGNED_INT = 0x004,
+	FLOAT = 0x304,
+	HALF_FLOAT = 0x302
 };
 
-unsigned get_type_size(DataType);
+inline unsigned get_type_size(DataType t)
+{ return t&0xFF; }
+
+GLenum get_gl_type(DataType);
 
 } // namespace GL
 } // namespace Msp
diff --git a/source/core/texture1d.cpp b/source/core/texture1d.cpp
index 742857be..1e90b6f7 100644
--- a/source/core/texture1d.cpp
+++ b/source/core/texture1d.cpp
@@ -75,7 +75,7 @@ void Texture1D::image(unsigned level, const void *data)
 	}
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	glTexImage1D(target, level, storage_fmt, w, 0, comp, type, data);
 
 	allocated |= 1<<level;
@@ -102,7 +102,7 @@ void Texture1D::sub_image(unsigned level, int x, unsigned wd, const void *data)
 	allocate(level);
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	if(ARB_direct_state_access)
 		glTextureSubImage1D(id, level, x, wd, comp, type, data);
 	else
diff --git a/source/core/texture2d.cpp b/source/core/texture2d.cpp
index 0e76128c..d2addda7 100644
--- a/source/core/texture2d.cpp
+++ b/source/core/texture2d.cpp
@@ -106,7 +106,7 @@ void Texture2D::image(unsigned level, const void *data)
 	}
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	glTexImage2D(target, level, storage_fmt, w, h, 0, comp, type, data);
 
 	allocated |= 1<<level;
@@ -133,7 +133,7 @@ void Texture2D::sub_image(unsigned level, int x, int y, unsigned wd, unsigned ht
 	allocate(level);
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	if(ARB_direct_state_access)
 		glTextureSubImage2D(id, level, x, y, wd, ht, comp, type, data);
 	else
diff --git a/source/core/texture3d.cpp b/source/core/texture3d.cpp
index 03c58d0a..1681f83c 100644
--- a/source/core/texture3d.cpp
+++ b/source/core/texture3d.cpp
@@ -94,7 +94,7 @@ void Texture3D::image(unsigned level, const void *data)
 	}
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	glTexImage3D(target, level, storage_fmt, width, height, depth, 0, comp, type, data);
 
 	allocated |= 1<<level;
@@ -121,7 +121,7 @@ void Texture3D::sub_image(unsigned level, int x, int y, int z, unsigned wd, unsi
 	allocate(level);
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	if(ARB_direct_state_access)
 		glTextureSubImage3D(id, level, x, y, z, wd, ht, dp, comp, type, data);
 	else
diff --git a/source/core/texturecube.cpp b/source/core/texturecube.cpp
index 6ec36625..d006e383 100644
--- a/source/core/texturecube.cpp
+++ b/source/core/texturecube.cpp
@@ -109,7 +109,7 @@ void TextureCube::image(TextureCubeFace face, unsigned level, const void *data)
 	}
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	glTexImage2D(face, level, storage_fmt, s, s, 0, comp, type, data);
 
 	if(level==0)
@@ -151,7 +151,7 @@ void TextureCube::sub_image(TextureCubeFace face, unsigned level, int x, int y,
 	allocate(level);
 
 	PixelComponents comp = get_components(storage_fmt);
-	DataType type = get_component_type(storage_fmt);
+	GLenum type = get_gl_type(get_component_type(storage_fmt));
 	glTexSubImage2D(face, level, x, y, wd, ht, comp, type, data);
 
 	if(auto_gen_mipmap && level==0)
-- 
2.43.0