drewcassidy/nvidia-texture-tools
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Try some optimizations.

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This commit is contained in:
castano 2008-10-01 22:28:01 +00:00
parent 2f6e885ced
commit b284669993
1 changed files with 45 additions and 1 deletions
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46
src/nvtt/OptimalCompressDXT.cpp
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@ -54,11 +54,23 @@ namespace
return d * d;
}
static uint nearestGreen4(uint green, uint maxGreen, uint minGreen)
{
uint bias = maxGreen + (maxGreen - minGreen) / 6;
uint index = 0;
if (maxGreen - minGreen != 0) index = clamp(3 * (bias - green) / (maxGreen - minGreen), 0U, 3U);
return (index * minGreen + (3 - index) * maxGreen) / 3;
}
static int computeGreenError(const ColorBlock & rgba, const BlockDXT1 * block, int bestError = INT_MAX)
{
nvDebugCheck(block != NULL);
// uint g0 = (block->col0.g << 2) | (block->col0.g >> 4);
// uint g1 = (block->col1.g << 2) | (block->col1.g >> 4);
int palette[4];
palette[0] = (block->col0.g << 2) | (block->col0.g >> 4);
palette[1] = (block->col1.g << 2) | (block->col1.g >> 4);
@ -77,6 +89,8 @@ namespace
totalError += error;
// totalError += nearestGreen4(green, g0, g1);
if (totalError > bestError)
{
// early out
@ -140,6 +154,36 @@ namespace
return q2 >> 4;
}
static uint nearestAlpha8(uint alpha, uint maxAlpha, uint minAlpha)
{
float bias = maxAlpha + float(maxAlpha - minAlpha) / (2.0f * 7.0f);
float scale = 7.0f / float(maxAlpha - minAlpha);
uint index = (uint)clamp((bias - float(alpha)) * scale, 0.0f, 7.0f);
return (index * minAlpha + (7 - index) * maxAlpha) / 7;
}
static uint computeAlphaError8(const ColorBlock & rgba, const AlphaBlockDXT5 * block, int bestError = INT_MAX)
{
int totalError = 0;
for (uint i = 0; i < 16; i++)
{
uint8 alpha = rgba.color(i).a;
totalError += alphaDistance(alpha, nearestAlpha8(alpha, block->alpha0, block->alpha1));
if (totalError > bestError)
{
// early out
return totalError;
}
}
return totalError;
}
static uint computeAlphaError(const ColorBlock & rgba, const AlphaBlockDXT5 * block, int bestError = INT_MAX)
{
uint8 alphas[8];
@ -268,7 +312,7 @@ void OptimalCompress::compressDXT1G(const ColorBlock & rgba, BlockDXT1 * block)
// Get min/max green.
for (uint i = 0; i < 16; i++)
{
uint8 green = rgba.color(i).g >> 2;
uint8 green = (rgba.color(i).g + 1) >> 2;
ming = min(ming, green);
maxg = max(maxg, green);