glsl: deduplicate RayIntersectDisplaceMap

[illwieckz]

RayIntersectDisplaceMap is already defined in reliefMapping_fp.glsl, doing the exact same thing:

Daemon/src/engine/renderer/glsl_source/reliefMapping_fp.glsl

Lines 203 to 253 in 9322bda

	float RayIntersectDisplaceMap(vec2 dp, vec2 ds, sampler2D normalMap)
	{
	const int linearSearchSteps = 16;
	const int binarySearchSteps = 6;
	float depthStep = 1.0 / float(linearSearchSteps);
	// current size of search window
	float size = depthStep;
	// current depth position
	float depth = 0.0;
	// best match found (starts with last position 1.0)
	float bestDepth = 1.0;
	// search front to back for first point inside object
	for(int i = 0; i < linearSearchSteps - 1; ++i)
	{
	depth += size;
	vec4 t = texture2D(normalMap, dp + ds * depth);
	if(bestDepth > 0.996) // if no depth found yet
	if(depth >= t.w)
	bestDepth = depth; // store best depth
	}
	depth = bestDepth;
	// recurse around first point (depth) for closest match
	for(int i = 0; i < binarySearchSteps; ++i)
	{
	size *= 0.5;
	vec4 t = texture2D(normalMap, dp + ds * depth);
	if(depth >= t.w)
	#ifdef RM_DOUBLEDEPTH
	if(depth <= t.z)
	#endif
	{
	bestDepth = depth;
	depth -= 2.0 * size;
	}
	depth += size;
	}
	return bestDepth;
	}

[slipher]

It would be good to make sure that the liquid shader is actually used first (see my comment on #172).

[illwieckz]

If the liquid shader is not used, it would explain #120

[illwieckz]

Hmm no, commenting out the #if !defined( GLSL_COMPILE_STARTUP_ONLY ) test does not fix that water issue, this is probably not related.

[slipher]

I checked my copy of station15 1.1 and it doesn't actually use the liquidMap keyword, which is required to activate these code paths. So no help in showing whether the code is used or works. Do you know some map that actually uses a liquidMap shader stage?

[illwieckz]

I think no one map use liquidStage yet. Like parallax, it's maybe entirely broken no one knows…
By the way the change is very straightforward, in any way it's better to have a cleaner code even if it's a dead code. This is to be sure any fix done to that parallax code is forwarded everywhere it is used. By deduplicating we make sure a potentially fixed bug will not resurface the day this code will be live again.