Redo encode32

fuzzie360 · fuzzie360 · commit 28278d5eedcc · 2016-03-01T19:52:53.000+08:00
diff --git a/src/backend/mode_gpu.js b/src/backend/mode_gpu.js
@@ -290,9 +290,7 @@
 					'varying vec2 vTexCoord;',
 					'',
 					'float actuallyMod(float x, float y) {',
-					'	float f = mod(x, y);',
-					'	if (abs(f-y) < 0.001) return 0.0;',
-					'	return f;',
+					'	return x - y * floor(x/y);',
 					'}',
 					'',
 					opt.offsetRangeHack ? '#define OFFSET_HACK' : '',
@@ -317,11 +315,11 @@
 					'highp float decode32(highp vec4 rgba) {',
 					(endianness == 'LE' ? '' : '	rgba.rgba = rgba.abgr;'),
 					'	rgba *= 255.0;',
-					'	highp float sign = 1.0 - step(128.0,rgba.a)*2.0;',
-					'	highp float exponent = 2.0 * actuallyMod(rgba.a,128.0) + step(128.0,rgba.b) - 127.0; ',
-					'	highp float mantissa = actuallyMod(rgba.b,128.0)*65536.0 + rgba.g*256.0 +rgba.r + float(0x800000);',
-					'	highp float result =  sign * exp2(exponent) * (mantissa * exp2(-23.0 )); ',
-					'	return result;',
+					'	float sign = 1.0 - step(128.0,rgba.a)*2.0;',
+					'	float exponent = 2.0 * actuallyMod(rgba.a,128.0) + step(128.0,rgba.b) - 127.0;',
+					'	if (abs(exponent + 127.0) < 0.001) return 0.0;',
+					'	float mantissa = actuallyMod(rgba.b,128.0)*65536.0 + rgba.g*256.0 +rgba.r+ float(0x800000);',
+					'	return sign * exp2(exponent-23.0) * mantissa;',
 					'}',
 					'/* End: http://stackoverflow.com/questions/7059962/how-do-i-convert-a-vec4-rgba-value-to-a-float */',
 					'#else',
@@ -370,6 +368,8 @@
 					'	float index = (xyz.z * texDim.x * texDim.y) + (xyz.y * texDim.x) + xyz.x;',
 					'	float t = floor(index / texSize.x);',
 					'	float s = actuallyMod(index, texSize.x);',
+					'	s += 0.5;',
+					'	t += 0.5;',
 					(opt.safeTextureReadHack ? 's += 1.0; t += 1.0;' : ''),
 					(opt.safeTextureReadHack ? 'return decode32(texture2D(tex, vec2(s / (texSize.x + 2.0), t / (texSize.y + 2.0))));' : ''),
 					'	return decode32(texture2D(tex, vec2(s / texSize.x, t / texSize.y)));',
