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OpenGL no image when i use both textures

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I have a problem with mixing two textures in the shader. One texture is a heightmap that i also use to shade my heights, and the other texture is a skybox for reflection. As long as I only use one texture to define the color of my fragment, everything works fine, until I start mixing those colors in the fragment shader, then the model is not rendered anymore at all. A fun fact is, that it not the problem to use both textures at the same time, because I use the heightmap all the time to define the height of the vertex, but as soon as the fragment is dependent from both textures i dont see anything anymore.

Here is a part of my sourcecode, please let me know if there is anything missing, so that you can answer my question properly

loading of the heightmap (8 bpp)

val textureHeightMap = glGenTextures
glBindTexture(GL_TEXTURE_2D, textureHeightMap)
glTexImage2D(GL_TEXTURE_2D, 0, GL_INTENSITY8, width, height, 0, GL_INTENSITY,GL_UNSIGNED_BYTE, data)

loading of the cubemap (32 pbb)

val textureCubeMap = glGenTextures
glBindTexture(GL_TEXTURE_CUBE_MAP, textureCubeMap);
//Define all 6 faces
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, allData(0) );
glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, allData(1) );
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, allData(2) );
glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, allData(3) );
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, allData(4) );
glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, allData(5) );

the drawing function of my mesh

//shader is an object that encapsulates a linked shader program.
shader.setUniform(textureLoc, 0)
shader.setUniform(skyboxLoc, 1)

glBindTexture(GL_TEXTURE_2D, textureHeightMap)
glBindTexture(GL_TEXTURE_CUBE_MAP, textureHeightMap)


this is my fragment shader, it is just phong lighting added with reflection to cube map.

uniform vec3 u_lightDirection;
uniform sampler2D u_texture;
uniform samplerCube u_skybox;
uniform float u_width;
uniform vec3 u_camPos;

in vec3 v_pos;
in vec3 v_Normal;
in vec3 v_Dir;
in vec3 v_color;

out vec4 fragColor;

void main(void) {
float diffuse = max(dot(-u_lightDirection,normalize(v_Normal)),0)*0.9;
float phong = pow(max(dot(-normalize(u_lightDirection), reflect( v_Dir, normalize(v_Normal))), 0), 23);
float ambient = 0.5f;

vec2 texCoord = v_pos.xy/u_width;

float r = 0.5;

//vec4 col = r*texture(u_texture,texCoord);
vec4 col = r*vec4(v_color,1);
vec4 refl = (1-r)*texture(u_skybox,reflect(u_camPos-v_pos, v_Normal));

fragColor = vec4(diffuse+ambient)*col+refl+vec4(phong);


hope you don't mind that I did not post my entire sourcecode, just tho parts I think that are important. If you are courious about the sytax, it is Scala, a JVM language, so it is a wrapped opengl (lwjgl). Semicolons and braces for no-arg functions are not needed.

Thanks for your help

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Yay I solved it, sorry to bother you, in the end the error was not in the code that I've offered here. I did not implement the shader.setUniform method with an int only with a float. The compiler didn't tell me that it was autocasting and in the end that was the error.

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