GLuint NvCreateTextureFromDDSEx(const char* filename, NvBool flipVertical, NvBool useMipmaps, int* width, int* height, NvBool* alpha, NvBool *isCubeMap)
{
// Clear the GL error before this function, since at the end of this
// function, we test the error and report it. We do not want to report
// an error that happened at some random time before. If we want to
// catch those, we need more general/comprehensive handling. But having
// this function print a GL error for something that happened in other
// random code is confusing, especially to non-rail developers.
// Some other code, like NVBitfont, prints error messages at the top of
// the function and print a message that implies that the error was there
// at the time of call. That may make sense as an optional setting down
// the road
glGetError();
GLuint tex = 0;
NVHHDDSImage *img = NVHHDDSLoad(filename, flipVertical ? 1 : 0);
if (img)
{
if(isCubeMap)
{
*isCubeMap = img->cubemap ? NV_TRUE:NV_FALSE;
}
if (width)
*width = img->width;
if (height)
*height = img->height;
if (alpha)
*alpha = img->alpha ? NV_TRUE : NV_FALSE;
glGenTextures(1, &tex);
if (!img->cubemap)
{
glBindTexture(GL_TEXTURE_2D, tex);
LoadTextureFromDDSData(GL_TEXTURE_2D, 0, img, useMipmaps);
}
else
{
int baseLevel = 0;
glBindTexture(GL_TEXTURE_CUBE_MAP, tex);
LoadTextureFromDDSData(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, baseLevel, img, useMipmaps);
baseLevel += img->numMipmaps ? img->numMipmaps : 1;
LoadTextureFromDDSData(GL_TEXTURE_CUBE_MAP_POSITIVE_X, baseLevel, img, useMipmaps);
baseLevel += img->numMipmaps ? img->numMipmaps : 1;
LoadTextureFromDDSData(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, baseLevel, img, useMipmaps);
baseLevel += img->numMipmaps ? img->numMipmaps : 1;
LoadTextureFromDDSData(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, baseLevel, img, useMipmaps);
baseLevel += img->numMipmaps ? img->numMipmaps : 1;
LoadTextureFromDDSData(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, baseLevel, img, useMipmaps);
baseLevel += img->numMipmaps ? img->numMipmaps : 1;
LoadTextureFromDDSData(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, baseLevel, img, useMipmaps);
baseLevel += img->numMipmaps ? img->numMipmaps : 1;
}
GLint err = glGetError();
if (err)
NVLogError("NvCreateTextureFromDDSEx error", "");
NVHHDDSFree(img);
}
return tex;
}
bool createNormalMapGL(GLuint &textureID, const unsigned int index,
const GLenum textureUnit, const GLfloat heightScale,
const char *filename)
{
//Temporary variables for loading pixel data
unsigned char* pHeightPixels, *pNormalPixels;
unsigned int uiFormat, uiType, uiWidth, uiHeight;
NVHHDDSImage *img = NVHHDDSLoad(filename, (NvS32)1);
if(!img)
{
DEBUG("ERROR createNormalMapGL: problem loading height map texture.");
return false;
}
pHeightPixels = (unsigned char*)(img->data[0]);
uiWidth = (unsigned int) (img->width);
uiHeight = (unsigned int) (img->height);
uiFormat = (unsigned int) (img->format);
uiType = (unsigned int) (img->componentFormat);
unsigned int uiFormatWidth = 4U;
pNormalPixels = new unsigned char[uiWidth * uiHeight * uiFormatWidth];
for(unsigned int j = 0U; j < uiHeight; j++)
for(unsigned int i = 0U; i < uiWidth; i++)
{
unsigned int iCenterIdx = uiFormatWidth * (j * uiWidth + i);
unsigned int iLeftIdx = uiFormatWidth * ((i > 0U) ?
( j * uiWidth + (i - 1U)) :
( j * uiWidth + (uiWidth - 1U)));
unsigned int iRightIdx = uiFormatWidth * ((i < uiWidth - 1U) ?
( j * uiWidth + (i + 1U)) :
( j * uiWidth + 0U ));
unsigned int iUpIdx = uiFormatWidth * ((j > 0U) ?
((j - 1U) * uiWidth + i ) :
((uiHeight - 1U) * uiWidth + i ));
unsigned int iDownIdx = uiFormatWidth * ((j < uiHeight - 1U) ?
((j + 1U) * uiWidth + i ) :
( 0U * uiWidth + i ));
GLfloat fDx, fDy, fDz;
//Compute gradients
fDx = (GLfloat)(pHeightPixels[iRightIdx]); //[ 0, 255]
fDy = (GLfloat)(pHeightPixels[iUpIdx]); //[ 0, 255]
fDx -= (GLfloat)(pHeightPixels[iLeftIdx]); //[-255, 255]
fDy -= (GLfloat)(pHeightPixels[iDownIdx]); //[-255, 255]
fDx /= 255.0F; //[ -1, 1]
fDy /= 255.0F; //[ -1, 1]
//Scale them
fDx *= heightScale; //[ -H, H]
fDy *= heightScale; //[ -H, H]
//Putting them in vectors (1, 0, fDx) and (0, 1, fDy) and
//doing a cross product results in (-fDx, -fDy, 1)
//BUT, for some reason, fDx needs to be turned into its
//negative again for normal mapping to work, so we will only
//turn fDy into its negative
fDy *= -1; //[ -H, H]
//We normalize the vector
GLfloat fDet = (GLfloat)(sqrt(fDx * fDx + fDy * fDy + 1.0));
fDx /= fDet; fDy /= fDet; //[ -1, 1]
//Now, we have to fit them into unsigned chars. We map them from
//[-1, 1] to [0, 255]
fDx += 1.0F; fDy += 1.0F; //[ 0, 2]
fDx *= 128.0F; fDy *= 128.0F; //[ 0, 255]
//The z component of the vector is just 1
//(not scaled, but normalized)
fDz = (GLfloat)1.0F / fDet; //[ 0, 1]
fDz *= 255.0F;
pNormalPixels[iCenterIdx + 0U] = (unsigned char)fDx;
pNormalPixels[iCenterIdx + 1U] = (unsigned char)fDy;
pNormalPixels[iCenterIdx + 2U] = (unsigned char)fDz;
pNormalPixels[iCenterIdx + 3U] = pHeightPixels[iCenterIdx];
}
NVHHDDSFree(img);
glGenTextures(1, &(textureID));
glActiveTexture(textureUnit);
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, (GLint)0, (GLint)uiFormat,
(GLsizei)uiWidth, (GLsizei)uiHeight, (GLint)0,
(GLenum)uiFormat, (GLenum)uiType,
(const GLvoid*)pNormalPixels);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
delete [] pNormalPixels;
return true;
}
