Fixed bad logic for ref/simd path.

src/image.cpp

@@ -3,60 +3,55 @@
  * License: http://www.opensource.org/licenses/BSD-2-Clause
  */
 
+#include "bgfx_p.h"
 #include <bx/float4_t.h>
 
 namespace bgfx
 {
 	static void imageSwizzleBGRA8Ref(uint8_t* _rgbaData, uint32_t _width, uint32_t _height) 
 	{
-		uint32_t dstpitch = _width*4;
-		for (uint32_t yy = 0; yy < _height; ++yy)
+		const uint32_t dstpitch = _width*4;
+		uint8_t* ptr = _rgbaData;
+
+		for (uint32_t xx = 0, num = _width*_height; xx < num; ++xx)
 		{
-			uint8_t* dst = &_rgbaData[yy*dstpitch];
-
-			for (uint32_t xx = 0; xx < _width; ++xx)
-			{
-				uint8_t tmp = dst[0];
-				dst[0] = dst[2];
-				dst[2] = tmp;
-				dst += 4;
-			}
+			uint8_t tmp = ptr[0];
+			ptr[0] = ptr[2];
+			ptr[2] = tmp;
+			ptr += 4;
 		}
 	}
 
 	void imageSwizzleBGRA8(uint8_t* _rgbaData, uint32_t _width, uint32_t _height)
 	{
-		if (0 != (_width&0xf)
-		||  _width < 16)
+		// Test can we do four 4-byte pixels at the time.
+		if (0 != (_width&0x3)
+		||  _width < 4)
 		{
+			BX_WARN(_width < 4, "Image swizzle is taking slow path. Image width must be multiple of 4 (width %d).", _width);
 			imageSwizzleBGRA8Ref(_rgbaData, _width, _height);
 			return;
 		}
 
-		uint32_t dstpitch = _width*4;
-		uint32_t num = dstpitch/16;
+		const uint32_t dstpitch = _width*4;
 
 		using namespace bx;
 
 		const float4_t mf0f0 = float4_isplat(0xff00ff00);
 		const float4_t m0f0f = float4_isplat(0x00ff00ff);
+		uint8_t* ptr = _rgbaData;
 
-		for (uint32_t yy = 0; yy < _height; ++yy)
+		for (uint32_t xx = 0, num = dstpitch/16*_height; xx < num; ++xx)
 		{
-			uint8_t* ptr = &_rgbaData[yy*dstpitch];
-
-			for (uint32_t xx = 0; xx < num; ++xx)
-			{
-				const float4_t tabgr = float4_ld(ptr);
-				const float4_t t00ab = float4_srl(tabgr, 16);
-				const float4_t tgr00 = float4_sll(tabgr, 16);
-				const float4_t tgrab = float4_or(t00ab, tgr00);
-				const float4_t ta0g0 = float4_and(tabgr, mf0f0);
-				const float4_t t0g0b = float4_and(tgrab, m0f0f);
-				const float4_t targb = float4_or(ta0g0, t0g0b);
-				float4_st(ptr, targb);
-				ptr += 16;
-			}
+			const float4_t tabgr = float4_ld(ptr);
+			const float4_t t00ab = float4_srl(tabgr, 16);
+			const float4_t tgr00 = float4_sll(tabgr, 16);
+			const float4_t tgrab = float4_or(t00ab, tgr00);
+			const float4_t ta0g0 = float4_and(tabgr, mf0f0);
+			const float4_t t0r0b = float4_and(tgrab, m0f0f);
+			const float4_t targb = float4_or(ta0g0, t0r0b);
+			float4_st(ptr, targb);
+			ptr += 16;
 		}
 	}