Flat shader about magnum HOT 6 CLOSED

The main cause should be fixed in ef83211 (why the heck the compiler issued only a warning?!), but the issue shouldn't happen on GL 3.3 in the first place, only on GL < 3.2 (as ARB_explicit_attrib_location isn't supported there). Also, I couldn't find any issue with textured-triangle example. Is the shader compiler printing similar warning?

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I'm not sure why, but I'm still getting black instead of the texture. At first I thought it was my image loading code, but it's not. As you can see below.

But I just keep getting a black triangle when trying to get it to work with magnum.

The image I load uses stb_image, and it is in RGBA8 format.

Here's my image loading code:

auto imageData = util::loadImage("stone.jpg");
Magnum::ImageReference2D image{Magnum::ColorFormat::RGBAInteger, 
Magnum::ColorType::UnsignedByte,
 {imageData.width, imageData.height}, 
imageData.pixels.get()};

texture.setWrapping(Magnum::Sampler::Wrapping::ClampToEdge)
.setMagnificationFilter(Magnum::Sampler::Filter::Linear)
.setMinificationFilter(Magnum::Sampler::Filter::Linear)
.setImage(0, Magnum::TextureFormat::RGBA8, image);

Here's my code to set up the buffers/mesh object(s):

struct vertex
{
   Vector2 position;
   //Color4 colour;
   Vector2 textureCoords;
};
const int SIZE = 3;
constexpr static std::array<vertex, SIZE> vertices{{
        { {-300, -300}, /*{},*/ {0, 0} },
        { {300, -300}, /*{},*/  {1, 0} },
        { {0, 300}, /*{},*/ {0.5f, 1} },
}};

buffer.setData(vertices, Magnum::Buffer::Usage::StaticDraw);

mesh.setPrimitive(Mesh::Primitive::TriangleStrip).setVertexCount(SIZE)
.addVertexBuffer(buffer, 0, Shader::Position(), Shader::TextureCoordinates());

Here's my rendering code:

shader.setTransformationProjectionMatrix(Magnum::Matrix3::projection({640, 480}));
texture.bind(Magnum::Shaders::Flat2D::TextureLayer);

shader.use(); // this is a Flat2D shader

mesh.draw();

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Magnum::ColorFormat::RGBAInteger

I think one problem might be here. TextureFormat::RGBA8 should match ColorFormat::RGBA (or, in GL, the glTexImage2D() function requires GL_RGBA format for GL_RGBA8 internalFormat).

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If that doesn't help, try to trace the application in ApiTrace, if possible, and check for GL errors there, or manually pinpoint the GL error with the following:

Debug() << Renderer::error();

This prints GL error name if any occured since last call to Renderer::error() (or since the application started). Sadly OSX doesn't support proper OpenGL debug output yet, so there is no better approach to find the error.

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When I printed out the error after I uploaded the texture data, I got a:

Renderer::Error::InvalidOperation

And now I fixed this issue, by doing as you suggested and using ColorFormat::RGBA. Thank you. :)

I think I was just a bit confused, as there are various options you must provide for the format of the image. And I thought RGBAInteger was appropriate for my scenario.

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You're welcome, glad it's fixed :-) I should probably update the ColorFormat, ColorType and TextureFormat documentation and list values the user probably wants to use. The GL specification also isn't exactly helpful in this case, as information about the formats and allowed combinations is scattered around the whole document.

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