MultiTexturing/GLSL

[aidinh]

Hey Guy,

I got stuck in multi texturing and really long for some help. This is a part of the university assignment; I have to apply texture via GLSL. I really have no idea where the problem is. I am putting some parts of my code here and hope for receiving some advice. The shader and the main application file are in the separate files.

Thanks a million

const GLchar* VertexShader =
{
	"#version 330\n"\
 
	"layout(location=0) in vec4 in_Pos;\n"\
	"layout(location=1) in vec4 in_Color;\n"\
	"layout(location=2) in vec4 vNor;\n"\
	"layout(location=3) in vec2 vtexcoord;\n"\
 
	"out vec4 ex_Color;\n"\
	"out vec2 tex_coord;\n"\
 
	"uniform mat4 ModelViewMatrix;\n"\
	"uniform mat4 ProjectionMatrix;\n"\
 
	"void main(void)\n"\
	"{\n"\
	"	gl_Position = ProjectionMatrix*ModelViewMatrix*in_Pos/in_Pos.w;\n"\
	"	ex_Color = in_Color;\n"\
	"	tex_coord = vtexcoord;\n"\
	"}\n"
};
 
const GLchar* FragmentShader =
{
	"#version 330\n"\
 
	"in vec4 ex_Color;\n"\
	"in vec2 tex_coord;\n"\
 
	"uniform int VAONumber;\n"\
	"uniform sampler2D mytexP;\n"\
	"uniform sampler2D mytexR;\n"\
 
	"out vec4 out_Color;\n"\
 
	"void main(void)\n"\
	"{\n"\
	"	out_Color = ex_Color;\n"\
	"	if (VAONumber == 1) out_Color = ex_Color;\n"\
	"   if (VOANumber == 2) out_Color = ex_Color*texture(mytexP, vtexcoord.st) "
	"	if (VAONumber == 3) out_Color = ex_Color*texture(mytexR, vtexcoord.st);\n"\
 
 
	"}\n"
};

Key Board Function:

case '1': glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, textures[0]); printf("Text 0");break;
	case '2': glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, textures[1]); printf("Text 1");break;
	case '3': glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, textures[2]); printf("Text 2");break;

Render Function

void RenderFunction(void)
{
 
	int i,j;
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);
 
	glUniformMatrix4fv(ModelViewMatrixLocation, 1, 0, ModelViewMatrix);
	glUniformMatrix4fv(ProjectionMatrixLocation, 1, 0, ProjectionMatrix);
 
	VAONumber = 0; /* cube */
	glUniform1i(VAOLocation, VAONumber);
	glBindVertexArray(VAOIds[0]);
	glDrawArrays(GL_TRIANGLES, 0, 48);
 
 
	VAONumber = 2; /* plane */
	glUniform1i(VAOLocation, VAONumber);
	glUniform1i(textureLocP, 0);
	glActiveTexture(GL_TEXTURE0);
	glBindVertexArray(VAOIds[2]);
	glDrawArrays(GL_TRIANGLES, 0, 6);
 
 
	VAONumber = 1; /* roof */
	glUniform1i(VAOLocation, VAONumber);
	glUniform1i(textureLocR, 1);
	glActiveTexture(GL_TEXTURE1);
	glBindVertexArray(VAOIds[1]);
	glDrawArrays(GL_TRIANGLES, 0, 12);
 
	VAONumber = 3; /* axes */
	glUniform1i(VAOLocation, VAONumber);
    glBindVertexArray(VAOIds[3]);
    glDrawArrays(GL_LINES, 0, 6);
	glFlush();
 
	glBindVertexArray(0);
}

and the function for creating the vertex objects:

void CreateVBO(void)
{
 
	Vertex_t House_Tri[36]; /* vertices for cube triangles (3*triangles = 3*6*2) */
	Vertex_t Roof_Tri[12];  /* vertices for roof triangles (3*triangles = 3*2*2) */
	Vertex_t Plane_Tri[6]; /* 2 triangles */
 
	int i,j, ind;
	GLuint loc_tex;
 
	Image *Teximage;
 
	float v1[2], v2[2], v3[2], w1[2], w2[2], n1[2], n2[2], n3[2];
 
	/* House (Cube) triangles */
	ind = 0;
	for (i=0; i<12; i++) { /* 12:  number of triangles on a cube surface*/
		for (j=0; j<3; j++) { /* three vertices in each triangle */
			House_Tri[ind] = Cube_Ver[Cube_Ind[i*3+j]];
			ind = ind + 1;
		}
	}
 
	/* Roof triangles */
	ind = 0;
	for (i=0; i<4; i++) {
		for (j=0; j<3; j++) {
			Roof_Tri[ind] = Roof_Ver[Roof_Ind[i*3+j]];
			ind = ind + 1;
		}
	}
 
	/* triangles for the plane (colors and normals given in the data initialization) */
	ind = 0;
	for (i=0; i<2; i++) {
		for (j=0; j<3; j++) {
			Plane_Tri[ind] = Plane_Ver[Plane_Ind[i*3+j]];
			ind = ind + 1;
		}
	}
	/* texture coordinates for the plane (x,y,z) <-> (s,t) (always consists of two triangles) */
	/*                s                      t                                      */
	tex_coord[0][0] = 0.0; tex_coord[0][1] = 0.0; /* (s,t) (0,1) *********** (1,1) */
	tex_coord[1][0] = 1.0; tex_coord[1][1] = 0.0; /*            *       * *        */
	tex_coord[2][0] = 1.0; tex_coord[2][1] = 1.0; /*           *     *   *         */
	tex_coord[3][0] = 0.0; tex_coord[3][1] = 0.0; /*          *   *     *          */
	tex_coord[4][0] = 1.0; tex_coord[4][1] = 1.0; /*         * *       *           */
	tex_coord[5][0] = 0.0; tex_coord[5][1] = 1.0; /* (0,0)  ***********  (1,0)     */
 
	for (ind=0;ind<6;ind++) {
		Plane_Tri[ind].St[0] = tex_coord[ind][0]; Plane_Tri[ind].St[1] = tex_coord[ind][1];
	}
 
	glGenTextures(3, textures);	
	glActiveTexture(GL_TEXTURE0);	
	glBindTexture(GL_TEXTURE_2D, textures[0]);	
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 64, 64, 0, GL_RGB, GL_UNSIGNED_BYTE, checker1);	
	glGenerateMipmap(GL_TEXTURE_2D);
 
	glBindTexture(GL_TEXTURE_2D, textures[1]);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 64, 64, 0, GL_RGB, GL_UNSIGNED_BYTE, checker2);
	glGenerateMipmap(GL_TEXTURE_2D);
 
 
	Teximage = (Image *) malloc(sizeof(Image));
	ImageLoad("crate.bmp", Teximage);
	glActiveTexture(GL_TEXTURE1);
	glBindTexture(GL_TEXTURE_2D, textures[2]);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Teximage->sizeX, Teximage->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE,Teximage->data);
	glGenerateMipmap(GL_TEXTURE_2D);
 
	for (ind=0;ind<6;ind++) {
		Roof_Tri[ind].St[0] = tex_coord[ind][0]; Roof_Tri[ind].St[1] = tex_coord[ind][1];
		Roof_Tri[6+ind].St[0] = tex_coord[ind][0]; Roof_Tri[6+ind].St[1] = tex_coord[ind][1];
	}
 
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, textures[0]);
 
	glGenVertexArrays(4, &VAOIds[0]);
 
	glBindVertexArray(VAOIds[0]);
	glGenBuffers(3, &VBOIds[0]);
	glBindBuffer(GL_ARRAY_BUFFER, VBOIds[0]);
	glBufferData(GL_ARRAY_BUFFER, sizeof(House_Tri), House_Tri, GL_STATIC_DRAW);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4*14, 0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)16);
	glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)32);
	glEnableVertexAttribArray(0); glEnableVertexAttribArray(1);
	glEnableVertexAttribArray(2);
 
	glBindVertexArray(VAOIds[1]);
	glGenBuffers(4, &VBOIds[0]);
	glBindBuffer(GL_ARRAY_BUFFER, VBOIds[1]);
	glBufferData(GL_ARRAY_BUFFER, sizeof(Roof_Tri), Roof_Tri, GL_STATIC_DRAW);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4*14, 0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)16);
	glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)32);
	glVertexAttribPointer(3, 2, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)48);
	glEnableVertexAttribArray(0); glEnableVertexAttribArray(1);
	glEnableVertexAttribArray(2); glEnableVertexAttribArray(3);
 
	glBindVertexArray(VAOIds[2]);
	glGenBuffers(4, &VBOIds[0]);
	glBindBuffer(GL_ARRAY_BUFFER, VBOIds[2]);
	glBufferData(GL_ARRAY_BUFFER, sizeof(Plane_Tri), Plane_Tri, GL_STATIC_DRAW);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4*14, 0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)16);
	glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)32);
	glVertexAttribPointer(3, 2, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)48);
	glEnableVertexAttribArray(0); glEnableVertexAttribArray(1);
	glEnableVertexAttribArray(2); glEnableVertexAttribArray(3);
 
	glBindVertexArray(VAOIds[3]);
	glGenBuffers(3, &VBOIds[0]);
	glBindBuffer(GL_ARRAY_BUFFER, VBOIds[3]);
	glBufferData(GL_ARRAY_BUFFER, sizeof(Axes), Axes, GL_STATIC_DRAW);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4*14, 0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)16);
	glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, 4*14, (GLvoid*)32);
	glEnableVertexAttribArray(0); glEnableVertexAttribArray(1);
	glEnableVertexAttribArray(2);
 
    glBindVertexArray(0);
 
}

[thokra]

Could you please state what's going wrong? What are we looking for here?

[aidinh]

Hello,

I am expecting to be able to apply texture via keyboard commands, but getting wrong display. In fact, I am not sure that i am applying the texture in GLSL right. To be accurate, I have got some issues with following lines from fragment shader. I appreciate if you take look at it and let me have your comments.

Thank you very much

out_Color = ex_Color;
if (VAONumber == 1) out_Color = ex_Color;
if (VOANumber == 2) out_Color = ex_Color*texture(mytexP, vtexcoord.st);
if (VAONumber == 3) out_Color = ex_Color*texture(mytexR, vtexcoord.st);

[V-man]

Your render code just calls glActiveTexture but you aren't binding a texture (glBindTexture).

I can see that you are binding some texture where it says case 0, case 1, case 2. You seem to bind to GL_TEXTURE0 only.

[aidinh]

I do texture binding via keyboard function. Hope not doing any mistake.

case '1': glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, textures[0]); printf("Text 0");break;
case '2': glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, textures[1]); printf("Text 1");break;
case '3': glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, textures[2]); printf("Text 2");break;