take bilinear changes from cemu-project#879

this makes the shader consistent with hermite and fixes the wrong offset

src/Cafe/HW/Latte/Renderer/RendererOuputShader.cpp

@@ -48,24 +48,23 @@ vec4 cubic(float x)
 	return w / 6.0;
 }
 
-vec4 bcFilter(vec2 texcoord, vec2 texscale)
+vec4 bcFilter(vec2 uv, vec4 texelSize)
 {
-	float fx = fract(texcoord.x);
-	float fy = fract(texcoord.y);
-	texcoord.x -= fx;
-	texcoord.y -= fy;
+	vec2 pixel = uv*texelSize.zw - 0.5;
+	vec2 pixelFrac = fract(pixel);
+	vec2 pixelInt = pixel - pixelFrac;
 
-	vec4 xcubic = cubic(fx);
-	vec4 ycubic = cubic(fy);
+	vec4 xcubic = cubic(pixelFrac.x);
+	vec4 ycubic = cubic(pixelFrac.y);
 
-	vec4 c = vec4(texcoord.x - 0.5, texcoord.x + 1.5, texcoord.y - 0.5, texcoord.y + 1.5);
+	vec4 c = vec4(pixelInt.x - 0.5, pixelInt.x + 1.5, pixelInt.y - 0.5, pixelInt.y + 1.5);
 	vec4 s = vec4(xcubic.x + xcubic.y, xcubic.z + xcubic.w, ycubic.x + ycubic.y, ycubic.z + ycubic.w);
 	vec4 offset = c + vec4(xcubic.y, xcubic.w, ycubic.y, ycubic.w) / s;
 
-	vec4 sample0 = texture(textureSrc, vec2(offset.x, offset.z) * texscale);
-	vec4 sample1 = texture(textureSrc, vec2(offset.y, offset.z) * texscale);
-	vec4 sample2 = texture(textureSrc, vec2(offset.x, offset.w) * texscale);
-	vec4 sample3 = texture(textureSrc, vec2(offset.y, offset.w) * texscale);
+	vec4 sample0 = texture(textureSrc, vec2(offset.x, offset.z) * texelSize.xy);
+	vec4 sample1 = texture(textureSrc, vec2(offset.y, offset.z) * texelSize.xy);
+	vec4 sample2 = texture(textureSrc, vec2(offset.x, offset.w) * texelSize.xy);
+	vec4 sample3 = texture(textureSrc, vec2(offset.y, offset.w) * texelSize.xy);
 
 	float sx = s.x / (s.x + s.y);
 	float sy = s.z / (s.z + s.w);
@@ -76,7 +75,8 @@ vec4 bcFilter(vec2 texcoord, vec2 texscale)
 }
 
 void main(){
-	colorOut0 = vec4(bcFilter(passUV*inputResolution, vec2(1.0,1.0)/inputResolution).rgb,1.0);
+	vec4 texelSize = vec4( 1.0 / inputResolution.xy, inputResolution.xy);
+	colorOut0 = vec4(bcFilter(passUV, texelSize).rgb,1.0);
 }
 )";