Android NDK GLES 2.0 Nothing Drawing

I am trying to Draw with GLES 2.0 through the NDK, doing everything except creating the surface in C++, but nothing is drawing on the screen...And I can't figure out why.

I have tried/verified many different things and am still at a loss.

my last few guesses are these:

my textures are somehow now compatible with the screen:

I load textures like this:

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->GetPixels());

but the default GLSurfaceView format is RGB_565

I tried this with no success:

mGLView.getHolder().setFormat(PixelFormat.RGBA_8888);

and also this:

glTexImage2D(GL_TEXTURE_2D, 0, GL_UNSIGNED_SHORT_5_6_5, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->GetPixels());

could texture format have anything to do with the problem? I have no reference because the Android SDK abstracts this away completely..

this is the shader I am using:

const char *vertexShader = "\
    uniform mat4 uMtxProjection; \
    uniform mat4 uMtxModelView; \
    attribute vec2 aPosition; \
    attribute vec2 aTexCoord; \
    varying vec2 vTexCoord; \
    void main() \
    { \
        gl_Position = uMtxProjection * (uMtxModelView * vec4(aPosition.x, aPosition.y, 0.0, 1.0)); \
        vTexCoord = aTexCoord; \
    }";

const char *fragmentShader = "\
    precision mediump float; \
    varying vec2 vTexCoord; \
    uniform sampler2D sTexture; \
    void main() \
    { \
        gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0); \
    }";

After further testing, and removing the texture(filling triangle with only red) I can see a distorted red box flash exactly 3 times each time the app is run, then the 开发者_如何学JAVAscreen goes blank =/

and the ortho matrix:

Mat4 Ortho2D(float left, float right, float bottom, T top, float zNear, float zFar)
{
    float dx = right - left;
    float dy = top - bottom;
    float dz = zFar - zNear;

    // avoid division by zero
    float tx = (dx != 0) ? -(right + left) / dx : 0;
    float ty = (dy != 0) ? -(top + bottom) / dy : 0;
    float tz = (dz != 0) ? -(zFar + zNear) / dz : 0;

    return Mat4(2.0f / dx, 0,           0,          tx,
                0,          2.0f / dy, 0,           ty,
                0,          0,          -2.0f / dz, tz,
                0,          0,          0,          1);
}

---

Actually, I'm not sure what was going on exactly, but something I changed fixed the problem =/ I tried going back over the code to re-break it, but couldn't..

but for reference, I can't guarantee what was broken, but I can say for sure, that the problem was neither the texture, nor the shader. Even though the default surface view is set to RGB_565, using the following line creates a texture just fine in NDK, with working alpha.

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->GetPixels());

The projection matrix that I was using was also fine, because I copied it directly from the openGL specs.

I noticed while working that the call glEnable(TEXTURE_2D) was causing an error (invalid enum) because it pertains to the fixed function pipeline of opengl, and I was using GLES2.0... and I was copying some of my old code from a fixed function implementation GLES1. So all I can think of was that I was causing gl to crash somehow by with the old code =/