Commit 6de802e7 authored by Luis Penaranda's avatar Luis Penaranda
Browse files

pass ZB parameters to the shader automatically

parent d8c970c0

openglcanvas.cpp

+11 −5
Original line number Diff line number Diff line
@@ -709,11 +709,17 @@ void OpenGLCanvas::setShaders() { 


    GLuint p = glCreateProgram();



    // Bind attributes zblambda and zbR to the vertex shader

    glVertexAttrib1f(0,zblambda);

    glBindAttribLocation(p,0,"zblambda");

    glVertexAttrib1f(1,zbR);

    glBindAttribLocation(p,1,"zbR");

    // Bind attributes zblambda and zbR to the vertex shader. Nvidia hardware

    // only leaves attributes 1 and 7 unreserved; attributes 8 to 15 are

    // reserved for textures.

    // TODO: we use attributes 14 and 15, which work for Nvidia; we need to

    // test with other hardware.

#define ZBL_ATTR 14

#define ZBR_ATTR 15

    glVertexAttrib1f(ZBL_ATTR,zblambda);

    glBindAttribLocation(p,ZBL_ATTR,"zblambda");

    glVertexAttrib1f(ZBR_ATTR,zbR);

    glBindAttribLocation(p,ZBR_ATTR,"zbR");



    glAttachShader(p,v);

    glAttachShader(p,f);

shaders/test_vertex_shader.vert

+4 −8
Original line number Diff line number Diff line
@@ -6,9 +6,7 @@ float u, v, x, y, z; 
varying float r, theta, s;

float lambda, phi;

float extent, scale, vis_mode, center_lambda, center_phi;

float zbr,zbalpha,zbrho;

/*attribute*/ float zblambda;

/*attribute*/ float zbR;

attribute float zblambda,zbR;



void main(void){
@@ -87,11 +85,9 @@ void main(void){ 
        u=x/(-z);

        v=y/(-z);

        // Z-B transformation

        zblambda=0.1;

        zbR=1.0;

        zbalpha=atan(v,u);

        zbr=sqrt(u*u+v*v);

        zbrho=(zblambda*zbr/zbR)+(1.0-zblambda)*(zbR*(sqrt(zbr*zbr+1.0)-1.0))/(zbr*(sqrt(zbR*zbR+1.0)-1.0));

        float zbalpha=atan(v,u);

        float zbr=sqrt(u*u+v*v);

        float zbrho=(zblambda*zbr/zbR)+(1.0-zblambda)*(zbR*(sqrt(zbr*zbr+1.0)-1.0))/(zbr*(sqrt(zbR*zbR+1.0)-1.0));

        u=zbrho*cos(zbalpha);

        v=zbrho*sin(zbalpha);

        gl_Position = vec4(u/extent,v/extent,z,1.0);