here is the code I have so far
the screen turns grey 
no errors
and the test file for upbge current master (0.2.4 + )
bgl_DataTextures[0] = Normals
bgl_DataTextures[1] = Position
bgl_DataTextures[2] = spec
SSRTest4c.blend (1.8 MB)
uniform sampler2D bgl_RenderedTexture;
uniform sampler2D bgl_DepthTexture;
uniform sampler2D bgl_DataTextures[7];
uniform float bgl_RenderedTextureWidth;
uniform float bgl_RenderedTextureHeight;
vec2 gTexSizeInv= vec2(bgl_RenderedTextureWidth,bgl_RenderedTextureHeight);
// Consts should help improve performance
const float rayStep = 0.25;
const float minRayStep = 0.1;
const float maxSteps = 20;
const float searchDist = 5;
const float searchDistInv = 0.2;
const int numBinarySearchSteps = 5;
const float maxDDepth = 1.0;
const float maxDDepthInv = 1.0;
const float reflectionSpecularFalloffExponent = 3.0;
uniform mat4 projection;
vec3 BinarySearch(vec3 dir, inout vec3 hitCoord, out float dDepth)
{
float depth;
for(int i = 0; i < numBinarySearchSteps; i++)
{
vec4 projectedCoord = projection * vec4(hitCoord, 1.0);
projectedCoord.xy /= projectedCoord.w;
projectedCoord.xy = projectedCoord.xy * 0.5 + 0.5;
depth = texture2D(bgl_DataTextures[1], projectedCoord.xy).z;
dDepth = hitCoord.z - depth;
if(dDepth > 0.0)
hitCoord += dir;
dir *= 0.5;
hitCoord -= dir;
}
vec4 projectedCoord = projection * vec4(hitCoord, 1.0);
projectedCoord.xy /= projectedCoord.w;
projectedCoord.xy = projectedCoord.xy * 0.5 + 0.5;
return vec3(projectedCoord.xy, depth);
}
vec4 RayCast(vec3 dir, inout vec3 hitCoord, out float dDepth)
{
dir *= rayStep;
float depth;
for(int i = 0; i < maxSteps; i++)
{
hitCoord += dir;
vec4 projectedCoord = projection * vec4(hitCoord, 1.0);
projectedCoord.xy /= projectedCoord.w;
projectedCoord.xy = projectedCoord.xy * 0.5 + 0.5;
depth = texture2D(bgl_DataTextures[1], projectedCoord.xy).z;
dDepth = hitCoord.z - depth;
if(dDepth < 0.0)
return vec4(BinarySearch(dir, hitCoord, dDepth), 1.0);
}
return vec4(0.0, 0.0, 0.0, 0.0);
}
void main()
{
vec2 gTexCoord = gl_FragCoord.xy * gTexSizeInv;
// Samples
float specular = texture2D(bgl_RenderedTexture, gTexCoord).a;
if(specular == 0.0)
{
gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0);
return;
}
vec3 viewNormal = texture2D(bgl_DataTextures[0], gTexCoord).xyz;
vec3 viewPos = texture2D(bgl_DataTextures[1], gTexCoord).xyz;
// Reflection vector
vec3 reflected = normalize(reflect(normalize(viewPos), normalize(viewNormal)));
// Ray cast
vec3 hitPos = viewPos;
float dDepth;
vec4 coords = RayCast(reflected * max(minRayStep, -viewPos.z), hitPos, dDepth);
vec2 dCoords = abs(vec2(0.5, 0.5) - coords.xy);
float screenEdgefactor = clamp(1.0 - (dCoords.x + dCoords.y), 0.0, 1.0);
// Get color
gl_FragColor = vec4(texture2D(bgl_DataTextures[2], coords.xy).rgb,
pow(specular, reflectionSpecularFalloffExponent) *
screenEdgefactor * clamp(-reflected.z, 0.0, 1.0) *
clamp((searchDist - length(viewPos - hitPos)) * searchDistInv, 0.0, 1.0) * coords.w);
}
