Textures appear black in OpenGL 3.3 with GLSL - c++

Question

I have a problem with displaying textures with GLSL in OpenGL 3.3 (Core profile). I have triple-checked everything and still can't find mistake. I'm using SDL for window handling and for texture loading.
This is my texture loading function
glEnable (GL_TEXTURE_2D);
glGenTextures(1, &generated_texture);
glBindTexture(GL_TEXTURE_2D, generated_texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_BGRA, image->w, image->h, 0, GL_BGRA, GL_UNSIGNED_BYTE, image->pixels);
Passing to shaders
glActiveTexture(GL_TEXTURE0);
glUniform1i( glGetUniformLocation(shader, "texture_diffuse"), 0 );
glBindTexture(GL_TEXTURE_2D, texture_diffuse);
Vertex Shader
#version 330 core
struct Light
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec4 position;
};
struct Material
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec3 emission;
float shininess;
float reflectivity;
float ior;
float opacity;
};
layout(location = 0) in vec4 VertexPosition;
layout(location = 1) in vec3 VertexNormal;
layout(location = 2) in vec2 VertexTexture;
uniform mat4 PMatrix; //Camera projection matrix
uniform mat4 VMatrix; //Camera view matrix
uniform mat3 NMatrix; //MVMatrix ... -> converted into normal matrix (inverse transpose operation)
uniform mat4 MVPMatrix;
uniform Light light;
uniform Material material;
uniform sampler2D texture_diffuse;
//The prefix ec means Eye Coordinates in the Eye Coordinate System
out vec4 ecPosition;
out vec3 ecLightDir;
out vec3 ecNormal;
out vec3 ecViewDir;
out vec2 texture_coordinate;
void main()
{
ecPosition = VMatrix * VertexPosition;
ecLightDir = vec3(VMatrix * light.position - ecPosition);
ecNormal = NMatrix * VertexNormal;
ecViewDir = -vec3(ecPosition);
texture_coordinate = VertexTexture;
gl_Position = PMatrix * ecPosition;
}
Fragment Shader
#version 330 core
in vec3 ecNormal;
in vec4 ecPosition;
in vec3 ecLightDir;
in vec3 ecViewDir;
in vec2 texture_coordinate;
out vec4 FragColor;
struct Light
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec4 position;
};
struct Material
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec3 emission;
float shininess;
float reflectivity;
float ior;
float opacity;
};
uniform Light light;
uniform Material material;
uniform sampler2D texture_diffuse;
void main()
{
vec3 N = normalize(ecNormal);
vec3 L = normalize(ecLightDir);
vec3 V = normalize(ecViewDir);
float lambert = dot(N,L);
vec4 _tex = texture2D( texture_diffuse, texture_coordinate );
FragColor = _tex;
}
Also everything except textures works ( texture_coordinate etc. )
Does anyone see any possible error?

Answer 1

There are a few things I can see:
glEnable (GL_TEXTURE_2D);
This will just generate an error, as this enable is not valid in GL core profiles.
vec4 _tex = texture2D( texture_diffuse, texture_coordinate );
This will not compile, as the function texture2D is not available in GLSL3.30. It is called just texture and will derive the texture type from the sampler variable you call it with.
You should check for GL errors and especially the compile and link states of you shaders (and the info logs).