-bgfx: Revised fs_blit_palette16 to not use pixel rounding. Fixes issues in carpolo, kncljoe, and others. [Ryan Holtz] (#8488)

src/osd/modules/render/bgfx/shaders/chains/misc/fs_blit_palette16.sc

@@ -15,22 +15,7 @@ uniform vec4 u_inv_tex_size1;
 
 void main()
 {
-	// Logic taken from fs_blit_yuy16.sc - we need to do this, because
-	// the D3D9 BGFX backend claims to support RG8, but does so in
-	// a faulty way by using A8L8, which is not an appropriate format
-	// for representing an RG8 texture.
-	
-	vec2 half_texel = u_inv_tex_size0.xy * vec2(0.5, 0.5);
-	
-	vec2 original_uv = v_texcoord0.xy * u_tex_size0.xy;
-	float mod_val = mod(original_uv.x, 2.0);
-	vec2 rounded_uv = vec2(original_uv.x - mod_val, original_uv.y);
-	vec4 srcpix = texture2D(s_tex, rounded_uv * u_inv_tex_size0.xy + half_texel.x);
-
-	vec2 palette_uv = (srcpix.ra * vec2(256.0, 256.0)) * u_inv_tex_size1.xy;
-	if (mod_val < 1.0)
-		palette_uv = (srcpix.bg * vec2(256.0, 256.0)) * u_inv_tex_size1.xy;
-	
+	vec4 srcpix = texture2D(s_tex, v_texcoord0.xy);
+	vec2 palette_uv = (srcpix.bg * vec2(256.0, 256.0)) * u_inv_tex_size1.xy;
 	gl_FragColor = vec4(texture2D(s_pal, palette_uv).rgb, 1.0) * v_color0;
-	//gl_FragColor = texture2D(s_tex,  v_texcoord0) * v_color0;
 }

src/osd/modules/render/bgfxutil.cpp

@@ -17,23 +17,50 @@
 const bgfx::Memory* bgfx_util::mame_texture_data_to_bgfx_texture_data(bgfx::TextureFormat::Enum &dst_format, uint32_t src_format, int rowpixels, int height, const rgb_t *palette, void *base, uint16_t &out_pitch, int &convert_stride)
 {
 	bgfx::TextureInfo info;
+	const bgfx::Memory *data = nullptr;
+
 	switch (src_format)
 	{
-		case PRIMFLAG_TEXFORMAT(TEXFORMAT_PALETTE16):
 		case PRIMFLAG_TEXFORMAT(TEXFORMAT_YUY16):
 			dst_format = bgfx::TextureFormat::BGRA8;
 			convert_stride = 2;
 			out_pitch = rowpixels * 2;
+			bgfx::calcTextureSize(info, rowpixels / convert_stride, height, 1, false, false, 1, dst_format);
+
+			data = bgfx::copy(base, info.storageSize);
 			break;
+		case PRIMFLAG_TEXFORMAT(TEXFORMAT_PALETTE16):
+		{
+			dst_format = bgfx::TextureFormat::BGRA8;
+			convert_stride = 1;
+			out_pitch = rowpixels * 4;
+			bgfx::calcTextureSize(info, rowpixels / convert_stride, height, 1, false, false, 1, dst_format);
+
+			uint16_t *src = (uint16_t *)base;
+			uint16_t *dst_data = new uint16_t[rowpixels * 2 * height];
+			uint16_t *dst = dst_data;
+			for (int i = 0; i < rowpixels * height; i++, src++)
+			{
+				*dst++ = *src;
+				*dst++ = 0;
+			}
+
+			data = bgfx::copy(dst_data, info.storageSize);
+			delete [] dst_data;
+			break;
+		}
 		case PRIMFLAG_TEXFORMAT(TEXFORMAT_ARGB32):
 		case PRIMFLAG_TEXFORMAT(TEXFORMAT_RGB32):
 			dst_format = bgfx::TextureFormat::BGRA8;
 			convert_stride = 1;
 			out_pitch = rowpixels * 4;
+			bgfx::calcTextureSize(info, rowpixels / convert_stride, height, 1, false, false, 1, dst_format);
+
+			data = bgfx::copy(base, info.storageSize);
 			break;
 	}
-	bgfx::calcTextureSize(info, rowpixels / convert_stride, height, 1, false, false, 1, dst_format);
-	return bgfx::copy(base, info.storageSize);
+
+	return data;
 }
 
 const bgfx::Memory* bgfx_util::mame_texture_data_to_bgra32(uint32_t src_format, int width, int height, int rowpixels, const rgb_t *palette, void *base)