ok so this is my code:
vertex program:
// Uniform variables
uniform vec3 u_CameraPosition;
// Varying variables
varying float v_Distance;
varying vec2 v_Coordinates;
varying vec3 v_ViewDirection;
varying vec3 v_LightDirection;
// Attributes
attribute vec3 a_Tangent;
attribute vec3 a_Bitangent;
void main()
{
// Texture coordinates
v_Coordinates = gl_MultiTexCoord0.xy;
// Vertex position
vec4 VertexPosition = gl_ModelViewMatrix*gl_Vertex;
vec3 Tangent = gl_NormalMatrix*a_Tangent;
vec3 Bitangent = gl_NormalMatrix*a_Bitangent;
vec3 Normal = gl_NormalMatrix*gl_Normal;
// Light direction
vec3 LightVector = gl_LightSource[0].position.xyz-VertexPosition.xyz;
v_LightDirection.x = dot( Tangent, LightVector.xyz );
v_LightDirection.y = dot( Bitangent, LightVector.xyz );
v_LightDirection.z = dot( Normal, LightVector.xyz );
// Distance to light
v_Distance = length( LightVector );
// TBN matrix
mat3 TangentSpace;
TangentSpace[0] = Tangent;
TangentSpace[1] = Bitangent;
TangentSpace[2] = Normal;
v_ViewDirection= vec3(-VertexPosition)*TangentSpace ;
// Transform vertex
gl_Position = ftransform();
}
fragment program:
// Uniform variables
uniform float u_Factor;
uniform sampler2D u_Texture0;
uniform sampler2D u_Texture1;
uniform sampler2D u_Texture2;
// Varying variables
varying float v_Distance;
varying vec2 v_Coordinates;
varying vec3 v_ViewDirection;
varying vec3 v_LightDirection;
void main()
{
// Normalized light direction
vec3 LightDirection = normalize( v_LightDirection );
// Normalized Normal value
vec3 Normal = normalize( (texture2D(u_Texture1, v_Coordinates).xyz*2.0)-1.0 );
// Normal . light direction
float NdotL= dot( Normal, LightDirection );
// Reflection vector
vec3 Reflection = normalize( ((2.0*Normal )*NdotL)-LightDirection );
// Normalized view direction
vec3 ViewDirection = normalize( v_ViewDirection );
// Reflection . view direction
float RdotV = max( 0.0, dot(Reflection, ViewDirection) );
// Height value
float Height = (texture2D(u_Texture2, v_Coordinates).r)*u_Factor;
// Parallax'ed texture coordinates
vec2 Coordinates = v_Coordinates+(ViewDirection.xy*Height);
// Color value
vec4 Color = texture2D( u_Texture0, Coordinates );
// Final colors
vec4 TotalAmbient = gl_FrontMaterial.ambient*Color;
vec4 TotalDiffuse = gl_FrontMaterial.diffuse*NdotL*Color;
vec4 TotalSpecular = gl_FrontMaterial.specular*(pow(RdotV, gl_FrontMaterial.shininess));
// Summarize colors
gl_FragColor = TotalAmbient+TotalDiffuse+TotalSpecular;
}
take a look at the first screenshot:
can you see that the bricks are “facing” the camera? actually, you should see the top side of the bricks. so it seemed to me that the y-axis of the direction vector has to be inverted. i added this line to my fragment program:
// HACK!
ViewDirection = vec3( ViewDirection.x, -ViewDirection.y, ViewDirection.z );
and voila, it it seemed to work:
so i thought “strange, but who cares as long as it works”. but then i applied the shader to the floor, and the problem occured again… if i remove my hack from the shader, is looks correct on the floor - with the hack it looks correct on all other surfaces… the code is based on my bump mapping shader where everything worked fine. all i added is the distortion of the uv coordinates
what am i doing wrong? thanks!
i just realized that i’m not using my uniform u_CameraPosition at all in the vertex shader. but i guess i have to incorporate this, right? so far i’m simply passing the camera’s position to the shader, do i have to pre-multiply by the camera’s view matrix or sth like that?