bgfx/examples/common/cube_atlas.h
2013-04-22 22:42:11 +02:00

136 lines
5.7 KiB
C++

/* Copyright 2013 Jeremie Roy. All rights reserved.
* License: http://www.opensource.org/licenses/BSD-2-Clause
*/
#pragma once
/// Inspired from texture-atlas from freetype-gl (http://code.google.com/p/freetype-gl/)
/// by Nicolas Rougier (Nicolas.Rougier@inria.fr)
/// The actual implementation is based on the article by Jukka Jylänki : "A
/// Thousand Ways to Pack the Bin - A Practical Approach to Two-Dimensional
/// Rectangle Bin Packing", February 27, 2010.
/// More precisely, this is an implementation of the Skyline Bottom-Left
/// algorithm based on C++ sources provided by Jukka Jylänki at:
/// http://clb.demon.fi/files/RectangleBinPack/
#include <bgfx.h>
namespace bgfx
{
struct AtlasRegion
{
enum Type
{
TYPE_GRAY = 1, // 1 component
TYPE_BGRA8 = 4 // 4 components
};
uint16_t x, y;
uint16_t width, height;
uint32_t mask; //encode the region type, the face index and the component index in case of a gray region
Type getType()const { return (Type) ((mask >> 0) & 0x0000000F); }
uint32_t getFaceIndex()const { return (mask >> 4) & 0x0000000F; }
uint32_t getComponentIndex()const { return (mask >> 8) & 0x0000000F; }
void setMask(Type type, uint32_t faceIndex, uint32_t componentIndex) { mask = (componentIndex << 8) + (faceIndex << 4) + (uint32_t)type; }
};
class Atlas
{
public:
/// create an empty dynamic atlas (region can be updated and added)
/// @param textureSize an atlas creates a texture cube of 6 faces with size equal to (textureSize*textureSize * sizeof(RGBA))
/// @param maxRegionCount maximum number of region allowed in the atlas
Atlas(uint16_t textureSize, uint16_t _maxRegionsCount = 4096);
/// initialize a static atlas with serialized data (region can be updated but not added)
/// @param textureSize an atlas creates a texture cube of 6 faces with size equal to (textureSize*textureSize * sizeof(RGBA))
/// @param textureBuffer buffer of size 6*textureSize*textureSize*sizeof(uint32_t) (will be copied)
/// @param regionCount number of region in the Atlas
/// @param regionBuffer buffer containing the region (will be copied)
/// @param maxRegionCount maximum number of region allowed in the atlas
Atlas(uint16_t textureSize, const uint8_t * textureBuffer, uint16_t regionCount, const uint8_t* regionBuffer, uint16_t maxRegionsCount = 4096);
~Atlas();
/// add a region to the atlas, and copy the content of mem to the underlying texture
uint16_t addRegion(uint16_t width, uint16_t height, const uint8_t* bitmapBuffer, AtlasRegion::Type type = AtlasRegion::TYPE_BGRA8);
/// update a preallocated region
void updateRegion(const AtlasRegion& region, const uint8_t* bitmapBuffer);
/// Pack the UV coordinates of the four corners of a region to a vertex buffer using the supplied vertex format.
/// v0 -- v3
/// | | encoded in that order: v0,v1,v2,v3
/// v1 -- v2
/// @remark the UV are four signed short normalized components.
/// @remark the x,y,z components encode cube uv coordinates. The w component encode the color channel if any.
/// @param handle handle to the region we are interested in
/// @param vertexBuffer address of the first vertex we want to update. Must be valid up to vertexBuffer + offset + 3*stride + 4*sizeof(int16_t), which means the buffer must contains at least 4 vertex includind the first.
/// @param offset byte offset to the first uv coordinate of the vertex in the buffer
/// @param stride stride between tho UV coordinates, usually size of a Vertex.
void packUV( uint16_t regionHandle, uint8_t* vertexBuffer, uint32_t offset, uint32_t stride );
void packUV( const AtlasRegion& region, uint8_t* vertexBuffer, uint32_t offset, uint32_t stride );
/// Same as packUV but pack a whole face of the atlas cube, mostly used for debugging and visualizing atlas
void packFaceLayerUV(uint32_t idx, uint8_t* vertexBuffer, uint32_t offset, uint32_t stride );
/// Pack the vertex index of the region as 2 quad into an index buffer
void packIndex(uint16_t* indexBuffer, uint32_t startIndex, uint32_t startVertex )
{
indexBuffer[startIndex+0] = startVertex+0;
indexBuffer[startIndex+1] = startVertex+1;
indexBuffer[startIndex+2] = startVertex+2;
indexBuffer[startIndex+3] = startVertex+0;
indexBuffer[startIndex+4] = startVertex+2;
indexBuffer[startIndex+5] = startVertex+3;
}
/// return the TextureHandle (cube) of the atlas
bgfx::TextureHandle getTextureHandle() const { return m_textureHandle; }
//retrieve a region info
const AtlasRegion& getRegion(uint16_t handle) const { return m_regions[handle]; }
/// retrieve the size of side of a texture in pixels
uint16_t getTextureSize(){ return m_textureSize; }
/// retrieve the usage ratio of the atlas
//float getUsageRatio() const { return 0.0f; }
/// retrieve the numbers of region in the atlas
uint16_t getRegionCount() const { return m_regionCount; }
/// retrieve a pointer to the region buffer (in order to serialize it)
const AtlasRegion* getRegionBuffer() const { return m_regions; }
/// retrieve the byte size of the texture
uint32_t getTextureBufferSize() const { return 6*m_textureSize*m_textureSize*4; }
/// retrieve the mirrored texture buffer (to serialize it)
const uint8_t* getTextureBuffer() const { return m_textureBuffer; }
private:
void writeUV( uint8_t* vertexBuffer, int16_t x, int16_t y, int16_t z, int16_t w)
{
((uint16_t*) vertexBuffer)[0] = x;
((uint16_t*) vertexBuffer)[1] = y;
((uint16_t*) vertexBuffer)[2] = z;
((uint16_t*) vertexBuffer)[3] = w;
}
struct PackedLayer;
PackedLayer* m_layers;
uint32_t m_usedLayers;
uint32_t m_usedFaces;
bgfx::TextureHandle m_textureHandle;
uint16_t m_textureSize;
uint16_t m_regionCount;
uint16_t m_maxRegionCount;
AtlasRegion* m_regions;
uint8_t* m_textureBuffer;
};}