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How to get texture coordinate in GLSL in version 150?

In GLSL version 110, I can get the coordinate in gl_TexCoord [], but it is deprecated at 150.

OpenGL Code:

shader.setupShaderFromFile(GL_VERTEX_SHADER, "t.vert");
shader.setupShaderFromFile(GL_FRAGMENT_SHADER, "t.frag");
shader.linkProgram();

glGetFloatv(GL_MODELVIEW_MATRIX, modelview_mat_);
glGetFloatv(GL_PROJECTION_MATRIX, projectionview_mat_);

shader.begin();

glUniformMatrix4fv( glGetUniformLocation(shader.getProgram(), "MVMatrix"), 1, GL_FALSE, modelview_mat_);
glUniformMatrix4fv( glGetUniformLocation(shader.getProgram(), "MPMatrix"), 1, GL_FALSE, projectionview_mat_);

glBegin(GL_QUADS);
    glTexCoord2f(0, 0);glVertex2f(0, 0);
    glTexCoord2f(1, 0);glVertex2f(100, 0);
    glTexCoord2f(1, 1);glVertex2f(100, 100);
    glTexCoord2f(0, 1);glVertex2f(0, 100);
glEnd();

shader.end();

Shader Code:

VERTEX -

#version 150
in vec3 in_vertex;
in vec2 in_coord;
uniform mat4 MVMatrix;
uniform mat4 MPMatrix;

out vec2 tex_coord;

void main()
{
    vec4 v = vec4( in_vertex, 1.0 );

    tex_coord = in_coord;
    gl_Position = MPMatrix * MVMatrix * v;
}

FRAGMENT:

#version 150

in vec2 tex_coord;

out vec4 frgcolor;

void main()
{
    frgcolor = vec4( tex_coord, 0.0, 1.0);
}

The last screen is a red square.

How to pass texture coordinate to shader? or is my code wrong?

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2 answers

If you do not want to use obsolete methods, you will have to stop using glTexCoord2f and use a custom attribute.

If you want to stay with immediate mode, you will use glVertexAttrib2f .

You connect this to your new variable 'in_coord' by querying the index after binding the shader:

int program = glCreateProgram();
//create shader as normal
int texcoord_index = glGetAttribLocation(program, "in_coord");

glBegin(GL_QUADS);
glVertexAttrib2f(texcoord_index, 0, 0); ...

VA/VBO, glEnableVertexAttribArray/glVertexAttribPointer

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gl_TexCoord[0] . 1.5

++:

glActiveTexture(GL_TEXTURE0 );
glBindTexture(GL_TEXTURE_2D, id);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);

glMatrixMode(GL_TEXTURE);
glLoadIdentity();

glBegin(GL_QUADS);
    glTexCoord2f(0, 0);glVertex2f(0, 0);
    glTexCoord2f(1, 0);glVertex2f(100, 0);
    glTexCoord2f(1, 1);glVertex2f(100, 100);
    glTexCoord2f(0, 1);glVertex2f(0, 100);
glEnd();

:

gl_TexCoord[0]=gl_MultiTexCoord0;

:

vec4 c = texture2D(texSampler, gl_TexCoord[0].st );
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