Added loading multiple shader files for GlobalShaderFile option

Added a sharpen filter file as a global shader example.
Set TextureFilter to be enabled by default.

artifacts/ddraw.ini

@@ -53,10 +53,12 @@ WindowData=0
 
 ;Uncomment the option to use a hardware shader (requires DX9 graphics mode)
 ;The shader file <name>.fx must be placed in <GameRoot>\<master_patches>\shaders\ and must contain one technique with one or more passes
+;You can specify multiple shader files, separated by commas
 ;GlobalShaderFile=global.fx
 
 ;Set to 1 to enable linear texture filtering
-TextureFilter=0
+;This can be used in conjunction with GlobalShaderFile
+TextureFilter=1
 
 ;Set to 1 to do the palette conversion on the GPU
 ;Set to 2 to do the palette conversion on the CPU

artifacts/example_mods/GlobalShaders/sharpen.fx

@@ -0,0 +1,113 @@
+///////////////////////////////////////////////////////////////////////////////
+// Sharpen filter setting
+//
+// min: Sharpen 0.5,  EdgeSharpen  1.0
+// mid: Sharpen 1.0,  EdgeSharpen -0.25
+// max: Sharpen 1.75, EdgeSharpen -0.5  (1.5, -0.25)
+///////////////////////////////////////////////////////////////////////////////
+#define Sharpen      0.5
+#define EdgeSharpen  1.5
+
+
+texture sharpenTex;
+sampler s0;
+
+sampler SharpenSampler : samplerstate
+{
+	Texture = sharpenTex;
+	MinFilter = Linear;
+	MagFilter = Linear;
+	AddressU = Clamp;
+	AddressV = Clamp;
+};
+
+// Variables that set the width and height of the current game resolution from sfall
+float w;
+float h;
+
+static const float CoefBlur = (Sharpen * 0.5);
+static const float CoefOrig = (1 + CoefBlur);
+
+// for the sharpen edge
+#define SharpenEdge 0.4
+static const float sharpenVal0 = (Sharpen * (1.5 + EdgeSharpen));
+static const float sharpenVal1 = ((sharpenVal0 - 1) / 8.0);
+
+// pixel "width"
+static const float px = (1.0 / w);
+static const float py = (1.0 / h);
+
+// for the blur filter
+#define mean 1.0
+static const float dx = (mean * px);
+static const float dy = (mean * py);
+
+float4 SharpenComplexPS(float4 color : COLOR0, float2 texCoord : TEXCOORD0) : COLOR0
+{
+	float4 c0 = tex2D(s0, texCoord); // get original pixel
+
+	// edge detection
+	// Get neighbor points
+	// [ c1, c2, c3 ]
+	// [ c4, c0, c5 ]
+	// [ c6, c7, c8 ]
+	float4 c1 = tex2D(s0, texCoord + float2(-px, -py));
+	float4 c2 = tex2D(s0, texCoord + float2(  0, -py));
+	float4 c3 = tex2D(s0, texCoord + float2( px, -py));
+	float4 c4 = tex2D(s0, texCoord + float2(-px,   0));
+	float4 c5 = tex2D(s0, texCoord + float2( px,   0));
+	float4 c6 = tex2D(s0, texCoord + float2(-px,  py));
+	float4 c7 = tex2D(s0, texCoord + float2(  0,  py));
+	float4 c8 = tex2D(s0, texCoord + float2( px,  py));
+
+	// using Sobel filter
+	// horizontal gradient
+	// [ -1, 0, 1 ]
+	// [ -2, 0, 2 ]
+	// [ -1, 0, 1 ]
+	float delta1 = (c3 + 2 * c5 + c8) - (c1 + 2 * c4 + c6);
+
+	// vertical gradient
+	// [ -1, - 2, -1 ]
+	// [  0,   0,  0 ]
+	// [  1,   2,  1 ]
+	float4 c13 = c1 + c3;
+	float4 c68 = c6 + c8;
+	float delta2 = (c68 + 2 * c7) - (c13 + 2 * c2);
+
+	// computation
+	if (sqrt(mul(delta1, delta1) + mul(delta2, delta2)) > SharpenEdge) {
+		// if we have an edge, use sharpen
+		return c0 * sharpenVal0 - (c13 + c2 + c4 + c5 + c68 + c7) * sharpenVal1;
+
+		// Display edges in red...
+		//return float4( 1.0, 0.0, 0.0, 0.0 );
+	} else {
+		// else return corrected image
+
+		// compute blurred image (gaussian filter)
+		c1 = tex2D(s0, texCoord + float2(-dx, -dy));
+		c2 = tex2D(s0, texCoord + float2(  0, -dy));
+		c3 = tex2D(s0, texCoord + float2( dx, -dy));
+		c4 = tex2D(s0, texCoord + float2(-dx,   0));
+		c5 = tex2D(s0, texCoord + float2( dx,   0));
+		c6 = tex2D(s0, texCoord + float2(-dx,  dy));
+		c7 = tex2D(s0, texCoord + float2(  0,  dy));
+		c8 = tex2D(s0, texCoord + float2( dx,  dy));
+
+		// gaussian filter
+		// [ 1, 2, 1 ]
+		// [ 2, 4, 2 ]
+		// [ 1, 2, 1 ]
+		// to normalize the values, we need to divide by the coeff sum
+		float4 flou = (c1 + c3 + c6 + c8 + 2 * (c2 + c4 + c5 + c7) + 4 * c0) * 0.0625; // 1 / (1+2+1+2+4+2+1+2+1) = 1 / 16 = 0.0625
+
+		// substract blurred image from original image
+		return (CoefOrig * c0 - CoefBlur * flou);
+	}
+}
+
+technique SharpenT
+{
+	pass P0 { PixelShader = compile ps_2_0 SharpenComplexPS(); }
+}