increase height map resolution from 8 bit to 16 bit

pierstitus · Feb 10, 2021 · 48df931 · 48df931
1 parent 2a3882f
commit 48df931
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Showing 3 changed files with 12 additions and 5 deletions.
diff --git a/glsl/automaton.fsh b/glsl/automaton.fsh
@@ -55,7 +55,7 @@ vec2 coord(int dir) {
 }
 
 float elevation(int dir) {
-	return (zmax-zmin)*texture2D(elevationMap, coord(dir)).r/dw;
+	return (zmax-zmin)*(texture2D(elevationMap, coord(dir)).r + texture2D(elevationMap, coord(dir)).g/255.0)/dw;
 }
 
 float waterlevel(int dir) {

diff --git a/glsl/colormap.fsh b/glsl/colormap.fsh
@@ -37,7 +37,7 @@ vec4 col(float h) {
 }
 
 void main() {
-	float elevation = texture2D(elevationMap, v_texCoord).r;
+	float elevation = texture2D(elevationMap, v_texCoord).r + texture2D(elevationMap, v_texCoord).g/255.0;
 	float waterlayer = texture2D(waterlevelMap, v_texCoord).r + texture2D(waterlevelMap, v_texCoord).g/255.0;
 
 	if (elevation==0.0) gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);

diff --git a/index.html b/index.html
@@ -634,9 +634,16 @@
 					// write elevation data into texture data
 					var pixels = new Float32Array(width*height*4);
 					for (var i=0;i<data.length;i++) {
-						if (data[i]!=nodata) pixels[4*i] = (data[i]-zmin)/(zmax-zmin);
-						else pixels[4*i] = 0;
-						pixels[4*i+1] = 0;
+						if (data[i]!=nodata) {
+							var scaled = (data[i]-zmin)/(zmax-zmin) * 255.0;
+							var msb = Math.floor(scaled);
+							pixels[4*i] = msb / 255.0;
+							pixels[4*i+1] = scaled - msb;
+						}
+						else {
+							pixels[4*i] = 0;
+							pixels[4*i+1] = 0;
+						}
 						pixels[4*i+2] = 0;
 						pixels[4*i+3] = 0;
 					}