UPBGE: Fix specular tansparency value with depth transparency.

The depth transparency was computed with the input transparency and not the
current computed transparency which could be affected by the specular
transparency.
To fix this issue the input transparency passed to the GLSL function
shade_alpha_depth is the final transparency.

Author: panzergame

source/blender/gpu/intern/gpu_material.c

@@ -1975,7 +1975,7 @@ void GPU_shaderesult_set(GPUShadeInput *shi, GPUShadeResult *shr)
 		GPU_link(mat, "shade_alpha_depth",
 				 GPU_builtin(GPU_VIEW_POSITION),
 				 GPU_dynamic_texture_ptr(GPU_texture_global_depth_ptr(), GPU_DYNAMIC_SAMPLER_2DBUFFER, ma),
-				 shi->alpha, GPU_uniform(&ma->depthtranspfactor), &shr->alpha);
+				 shr->alpha, GPU_uniform(&ma->depthtranspfactor), &shr->alpha);
 	}
 
 	GPU_link(mat, "mtex_alpha_to_col", shr->combined, shr->alpha, &shr->combined);