Change slice syntax such that positions appear in parentheses

This allows to ignore slice declarations using `#define slice(x)`, which
mill be useful for custom mesh material shaders, allowing to write them
such that they can be used standalone in a mesh viewer but also as slices
for OpenClonk, in which case lighting and color modulation will be applied
automatically.

planet/Graphics.ocg/AmbientShader.glsl

@@ -6,13 +6,13 @@ uniform sampler2D ambientTex;
 uniform mat3x2 ambientTransform;
 uniform float ambientBrightness;
 
-slice texture+6
+slice(texture+6)
 {
 	// Ambient light
 	float ambient = texture2D(ambientTex, ambientTransform * vec3(gl_FragCoord.xy, 1.0)).r * ambientBrightness;
 }
 
-slice light+1
+slice(light+1)
 {
 	// Add ambience to brightness
 #ifdef LANDSCAPE

planet/Graphics.ocg/LandscapeShader.glsl

@@ -35,7 +35,7 @@ float queryMatMap(int pix)
 #endif
 }
 
-slice coordinate
+slice(coordinate)
 {
 	// full pixel steps in the landscape texture (depends on landscape resolution)
 	vec2 fullStep = vec2(1.0, 1.0) / resolution;
@@ -52,14 +52,14 @@ slice coordinate
 	vec2 materialCoo = texCoo * resolution / materialSize;
 }
 
-slice texture
+slice(texture)
 {
 	// our pixel color (without/with interpolation)
 	vec4 landscapePx = texture2D(landscapeTex[0], centerCoo);
 	vec4 realLandscapePx = texture2D(landscapeTex[0], texCoo);
 }
 
-slice material
+slice(material)
 {
 
 	// Get material pixels
@@ -75,7 +75,7 @@ slice material
 #endif
 }
 
-slice normal
+slice(normal)
 {
 	// Normal calculation
 	vec3 normal = extend_normal(mix(realLandscapePx.yz, landscapePx.yz, scalerPx.a)
@@ -91,7 +91,7 @@ slice normal
 
 }
 
-slice color {
+slice(color) {
 #define color gl_FragColor
 	color = materialPx;
 #ifdef HAVE_2PX

planet/Graphics.ocg/LightShader.glsl

@@ -13,7 +13,7 @@ uniform sampler2D lightTex;
 // and therefore will often never arrive at 0 light intensity.
 const float lightDarknessLevel = 8.0 / 256.0;
 
-slice texture+5
+slice(texture+5)
 {
 	// Query light texture
 	vec4 lightPx = texture2D(lightTex, lightCoord.st);
@@ -21,7 +21,7 @@ slice texture+5
 	vec3 lightDir = extend_normal(vec2(1.0, 1.0) - lightPx.yz * 3.0);
 }
 
-slice light
+slice(light)
 {
 	// Light direction
 	float light = 2.0 * lightBright * dot(normal, lightDir);
@@ -30,7 +30,7 @@ slice light
 #endif
 }
 
-slice color+5
+slice(color+5)
 {
 	// Add light
 	color = vec4(light * color.rgb, color.a);
@@ -39,7 +39,7 @@ slice color+5
 #endif
 }
 
-slice finish+5
+slice(finish+5)
 {
 
 #ifdef LIGHT_DEBUG

planet/Graphics.ocg/ScalerShader.glsl

@@ -1,7 +1,7 @@
 
 #define HAVE_2PX
 
-slice texture+5
+slice(texture+5)
 {
 	// find scaler coordinate
 	vec2 scalerCoo = scalerOffset + mod(pixelCoo, vec2(1.0, 1.0)) * scalerPixel;
@@ -43,7 +43,7 @@ slice texture+5
 
 }
 
-slice color+10 {
+slice(color+10) {
 	// Mix second color into main color according to scaler
 	color = mix(color2, color, scalerPx.r);
 }

planet/Graphics.ocg/SpriteBaseShader.glsl

@@ -1,13 +1,13 @@
 uniform vec4 clrMod;
 
-slice init
+slice(init)
 {
 #define color gl_FragColor
 	vec4 baseColor = gl_Color;
 	color = baseColor;
 }
 
-slice color
+slice(color)
 {
 	// TODO: Instead of a conditional, we could compute the color as
 	// color = A + B*color + C*clrMod + D*color*clrMod;

planet/Graphics.ocg/SpriteLightShader.glsl

@@ -3,13 +3,13 @@ uniform mat3x2 lightTransform;
 uniform sampler2D normalTex;
 #endif
 
-slice texture+4
+slice(texture+4)
 {
 	// prepare texture coordinate for light lookup in LightShader.c
 	vec2 lightCoord = lightTransform * vec3(gl_FragCoord.xy, 1.0);
 }
 
-slice normal
+slice(normal)
 {
 #ifdef HAVE_NORMALMAP
 	vec4 normalPx = texture2D(normalTex, texcoord.xy);

planet/Graphics.ocg/SpriteOverlayShader.glsl

@@ -1,7 +1,7 @@
 uniform vec4 overlayClr;
 uniform sampler2D overlayTex;
 
-slice texture+1
+slice(texture+1)
 {
 	// Get overlay color from overlay texture
 	vec4 overlay = baseColor * overlayClr * texture2D(overlayTex, texcoord.xy);
@@ -9,5 +9,3 @@ slice texture+1
 	float alpha0 = 1.0 - (1.0 - color.a) * (1.0 - overlay.a);
 	color = vec4(mix(color.rgb, overlay.rgb, overlay.a / alpha0), alpha0);
 }
-
-

planet/Graphics.ocg/SpriteTextureShader.glsl

@@ -1,6 +1,6 @@
 uniform sampler2D baseTex;
 
-slice texture
+slice(texture)
 {
 	color = baseColor * texture2D(baseTex, texcoord.xy);
 }

src/graphics/C4Shader.cpp

@@ -100,12 +100,19 @@ void C4Shader::AddSlices(const char *szWhat, const char *szText, const char *szS
 
 		// New slice? We need a newline followed by "slice"
 		if (iDepth < 0 && isspace(*pPos)) {
-			if (SEqual2(pPos+1, "slice") && isspace(*(pPos+6))) {
+			if (SEqual2(pPos+1, "slice") && !isalnum(*(pPos+6))) {
 				const char *pSliceEnd = pPos; pPos += 6;
+				while(isspace(*pPos)) pPos++;
+				if(*pPos != '(') { pPos++; continue; }
+				pPos++;
 
 				// Now let's parse the position
 				iPosition = ParsePosition(szWhat, &pPos);
 				if (iPosition != -1) {
+					// Make sure a closing parenthesis
+					while(isspace(*pPos)) pPos++;
+					if(*pPos != ')') { pPos++; continue; }
+					pPos++;
 
 					// Make sure an opening brace follows
 					while(isspace(*pPos)) pPos++;