Hi,
i try to render a quad with MVP-Matrix and an offset.
precision mediump float;
uniform mat4 u_mvpMatrix;
uniform vec2 u_offset;
attribute vec4 a_position;
attribute vec2 a_texCoord;
varying vec2 v_texCoord;
void main()
{
gl_Position =a_position;
gl_Position.x-=u_offset.x;
gl_Position *=u_mvpMatrix;
v_texCoord = a_texCoord;
}
run the opengl-code on X11 + SDL it looks right.
under raspberry pi2 without x the quad didn’t apear.
but when i remove the MVP-Matrix multiplacation:
precision mediump float;
uniform mat4 u_mvpMatrix;
uniform vec2 u_offset;
attribute vec4 a_position;
attribute vec2 a_texCoord;
varying vec2 v_texCoord;
void main()
{
gl_Position =a_position;
gl_Position.x-=u_offset.x;
//gl_Position *=u_mvpMatrix;
v_texCoord = a_texCoord;
}
the quad appears.
without the offset, with MVP-Matrix the quad appears, too.
precision mediump float;
uniform mat4 u_mvpMatrix;
uniform vec2 u_offset;
attribute vec4 a_position;
attribute vec2 a_texCoord;
varying vec2 v_texCoord;
void main()
{
gl_Position =a_position;
//gl_Position.x-=u_offset.x;
gl_Position *=u_mvpMatrix;
v_texCoord = a_texCoord;
}
why can’t i use MVP-Matrix mulltiplication and offset together on my raspberry pi2?
p.s.: my draw-function:
glUseProgram ( userData->programObject );
glUniformMatrix4fv( userData->mvpLoc, 1, GL_FALSE, (GLfloat*) &userData->mvpMatrix.m[0][0] );
glUniform2f(userData->offsetLoc, 0.5, 0.0);
glVertexAttribPointer ( userData->positionLoc, 3, GL_FLOAT, GL_FALSE, 0, userData->vertices );
glVertexAttribPointer ( userData->texCoordLoc, 2, GL_FLOAT, GL_FALSE, 0, userData->texCoord );
glDrawArrays ( GL_TRIANGLE_STRIP, 0, 4);