> "Normal" textures display correctly, but the shadow simply does not appear. > > Regards, > > Andreas > Hi,
I have solved this. The textur-coordinates for the shadow-texture are generated with texGen, so the vertex-shader has to simulate that. I use the following vertex-shader (which is based on a shader generated by ShaderGen): --------------------------------------shader begin /******************************************************* * Fixed.vert Fixed Function Equivalent Vertex Shader * * Automatically Generated by 3Dlabs GLSL ShaderGen * * http://developer.3dlabs.com * *******************************************************/ varying vec4 Ambient; vec4 Diffuse; vec4 Specular; varying vec4 Ambient2; void pointLight(in int i, in vec3 normal, in vec3 eye, in vec3 ecPosition3) { float nDotVP; // normal . light direction float nDotHV; // normal . light half vector float pf; // power factor float attenuation; // computed attenuation factor float d; // distance from surface to light source vec3 VP; // direction from surface to light position vec3 halfVector; // direction of maximum highlights // Compute vector from surface to light position VP = vec3 (gl_LightSource[i].position) - ecPosition3; // Compute distance between surface and light position d = length(VP); // Normalize the vector from surface to light position VP = normalize(VP); // Compute attenuation attenuation = 1.0 / (gl_LightSource[i].constantAttenuation + gl_LightSource[i].linearAttenuation * d + gl_LightSource[i].quadraticAttenuation * d * d); halfVector = normalize(VP + eye); nDotVP = max(0.0, dot(normal, VP)); nDotHV = max(0.0, dot(normal, halfVector)); if (nDotVP == 0.0) { pf = 0.0; } else { pf = pow(nDotHV, gl_FrontMaterial.shininess); } Ambient += gl_LightSource[i].ambient * attenuation; Diffuse += gl_LightSource[i].diffuse * nDotVP * attenuation; Specular += gl_LightSource[i].specular * pf * attenuation; } vec3 fnormal(void) { //Compute the normal vec3 normal = gl_NormalMatrix * gl_Normal; normal = normalize(normal); return normal; } void ftexgen(in vec3 normal, in vec4 ecPosition) { vec4 vertex = gl_ModelViewMatrix * gl_Vertex; gl_TexCoord[0] = gl_MultiTexCoord0; gl_TexCoord[1].s = dot( ecPosition, gl_EyePlaneS[1] ); gl_TexCoord[1].t = dot( ecPosition, gl_EyePlaneT[1] ); gl_TexCoord[1].p = dot( ecPosition, gl_EyePlaneR[1] ); gl_TexCoord[1].q = dot( ecPosition, gl_EyePlaneQ[1] ); } void flight(in vec3 normal, in vec4 ecPosition, float alphaFade) { vec4 color; vec3 ecPosition3; vec3 eye; ecPosition3 = (vec3 (ecPosition)) / ecPosition.w; eye = vec3 (0.0, 0.0, 1.0); // Clear the light intensity accumulators Ambient = vec4 (0.0); Diffuse = vec4 (0.0); Specular = vec4 (0.0); pointLight(0, normal, eye, ecPosition3); color = gl_FrontLightModelProduct.sceneColor + Ambient * gl_FrontMaterial.ambient + Diffuse * gl_FrontMaterial.diffuse; color += Specular * gl_FrontMaterial.specular; color = clamp( color, 0.0, 1.0 ); gl_FrontColor = color; Ambient2 = gl_FrontLightModelProduct.sceneColor + Ambient * gl_FrontMaterial.ambient; gl_FrontColor.a *= alphaFade; } void main (void) { vec3 transformedNormal; float alphaFade = 1.0; // Eye-coordinate position of vertex, needed in various calculations vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex; // Do fixed functionality vertex transform gl_Position = ftransform(); transformedNormal = fnormal(); if (dot(transformedNormal,vec3(0.0, 0.0, 1.0) )<0.0) transformedNormal = -1.0*transformedNormal; flight(transformedNormal, ecPosition, alphaFade); ftexgen(transformedNormal, ecPosition); } ------------------------------shader end The relevant part for you is the ftexgen-function. In the fragment shader I use the ambient2-color for the shadow, which then fits nicely to the rest of the scene. In the shader I simulate two-sided lighting by turning the normal towards the user: if (dot(transformedNormal,vec3(0.0, 0.0, 1.0) )<0.0) transformedNormal = -1.0*transformedNormal; This doesn´t give perfect results due to perspective. If someone has a better idea here, please tell me. Of course this shader only works if the shadowtexture uses texture-unit 1. Regards, Andreas > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
