Playbook shader problems

Playbook shader problems
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I hope someone can help me with this as I don’t seem to be making any progress. I am trying to do a (fairly) simple shader that will be a timer. It will remove segments of a image I pass in like a clock until it is all gone. My shaders are below and I have tested them running in a emulator through Visual Studio and it looks fine. When I load onto a Playbook through Momentics though it draws nothing.

Vertex Shader:

attribute vec4 a_position;
attribute vec2 a_texCoord;
attribute vec4 a_color;

uniform mat4 u_MVPMatrix;

#ifdef GL_ES
varying lowp vec4 v_fragmentColor;
varying mediump vec2 v_texCoord;
varying vec4 v_fragmentColor;
varying vec2 v_texCoord;

void main()
  gl_Position = u_MVPMatrix * a_position;
  v_fragmentColor = a_color;
  v_texCoord = a_texCoord;

Fragment Shader:

#ifdef GL_ES
precision highp float;

#define pi 3.141592653589793238462643383279

varying vec4 v_fragmentColor;
varying vec2 v_texCoord;
uniform sampler2D u_texture;
uniform float u_percent;

void main()
  vec4 text = texture2D(u_texture, v_texCoord);
  vec4 frag = v_fragmentColor;
  float pointX = v_texCoord.x - 0.5;
  float pointY = v_texCoord.y - 0.5;
  float tangent = atan(pointX,pointY * -1.0);

  tangent += pi;

  float within = pi * 2.0 * u_percent;

  bool test = tangent > within;

    frag.a = 0.0;
    frag.r = 0.0;
    frag.g = 0.0;
    frag.b = 0.0;
  gl_FragColor = frag * text;

To load my shader I do the following:

  CCSprite* mTimerImageOuter = CCSprite::spriteWithFile(ResourceSelector::getInstance()->layoutPath("player_avatar_timer_bg_outer.png").c_str());
  mTimerImageOuter->setPosition(ccp(mFrame->getContentSize().width * 0.5f, mFrame->getContentSize().height * 0.5f));


  std::string fragmentSource = ResourceSelector::getInstance()->path("circle_shader_frag.fsh");
  std::string vertexSource = ResourceSelector::getInstance()->path("circle_shader_vert.vsh");

  CCGLProgram *glProgram = new CCGLProgram();
  glProgram->initWithVertexShaderFilename(vertexSource.c_str(), fragmentSource.c_str());

  glProgram->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);

  ccBlendFunc blendFunc;

  blendFunc.src = GL_SRC_ALPHA;
  blendFunc.dst = GL_ONE_MINUS_SRC_ALPHA;


The only thing I have learned so far is if I change “gl_Position = u_MVPMatrix * a_position;” to “gl_Position = a_position;” in my vertex shader, I will draw a filled cube in the top right corner of the Playbook screen. So I think something is going wrong with my Model View Projection matrix but I have no idea what it could be.

Any help or guidance would be useful.