Having issues loading shaders

[carlosbispo]

Hi! Great work!
Im trying to follow a simple case with OpenGL.
I´m trying to draw a triangle and paint it using shaders. However I´m doing something wrong and I don´t know what is the problem.
Here is the source code in C:

// Drawing a triangle on screen with vertex array

#include <stdlib.h>
#include <stdio.h>


#include <vitaGL.h>
#include <string>
#include <vector>
#include <fstream>
#include <sstream>

// An array of 3 vectors which represents 3 vertices
static const float g_vertex_buffer_data[] = {
   -1.0f, -1.0f, 0.0f,
   1.0f, -1.0f, 0.0f,
   0.0f,  1.0f, 0.0f,
};

static const float colors[] = {1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0};

char *file_contents(const char *path);


char *file_contents(const char *path) {
	FILE *f = fopen(path, "r");
	// Read file size
	fseek(f, 0, SEEK_END);
	long fsize = ftell(f);
	fseek(f, 0, SEEK_SET);  /* same as rewind(f); */

	char *string = (char *)malloc(fsize + 1);
	fread(string, 1, fsize, f);
	
	fclose(f);
	
	return string;
}


GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path){

	// Create the shaders
	GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
	GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);
	
	GLint Result = GL_FALSE;
	int InfoLogLength;

	// Compile Vertex Shader
	printf("Compiling shader : %s\n", vertex_file_path);
	//GLchar *vertex_code;
	char *vertex_code = file_contents(vertex_file_path);
	//vertex_code = ;
	//strcpy(vertex_code, VertexShaderCode.c_str());
	const int32_t vertexSourceSize = strlen(vertex_code);
	glShaderSource(VertexShaderID, 1, &vertex_code , NULL);
	glCompileShader(VertexShaderID);
	// Check Vertex Shader
	glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result);
	
	if (!Result) {
		printf("Cant compile vertex code: %s\n", vertex_code);
	}	
	
	if ( InfoLogLength > 0 ){
		std::vector<char> VertexShaderErrorMessage(InfoLogLength+1);
		glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]);
		printf("%s\n", &VertexShaderErrorMessage[0]);
	}

	// Compile Fragment Shader
	printf("Compiling shader : %s\n", fragment_file_path);
	//GLchar *fragment_code;
	char *fragment_code = file_contents(fragment_file_path);
	printf("Codigo fragment: %s", fragment_code);
	
	const int32_t fragmentSourceSize = strlen(fragment_code);
	glShaderSource(FragmentShaderID, 1, &fragment_code , &fragmentSourceSize);
	glCompileShader(FragmentShaderID);

	// Check Fragment Shader
	glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
	
	if (!Result) {
		printf("Cant compile fragment code: %s\n", vertex_code);
	}	
	
	glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
	if ( InfoLogLength > 0 ){
		std::vector<char> FragmentShaderErrorMessage(InfoLogLength+1);
		glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
		printf("%s\n", &FragmentShaderErrorMessage[0]);
	}

	// Link the program
	printf("Linking program\n");
	GLuint ProgramID = glCreateProgram();
	printf("Program:%d\n", ProgramID);
	glAttachShader(ProgramID, FragmentShaderID);
	glAttachShader(ProgramID, VertexShaderID);
	
	glLinkProgram(ProgramID);

	// Check the program
	/*
	glGetProgramiv(ProgramID, GL_LINK_STATUS, &Result);
	glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength);
	if ( InfoLogLength > 0 ){
		std::vector<char> ProgramErrorMessage(InfoLogLength+1);
		glGetProgramInfoLog(ProgramID, InfoLogLength, NULL, &ProgramErrorMessage[0]);
		printf("%s\n", &ProgramErrorMessage[0]);
	}
	*/
	
	
	//glDetachShader(ProgramID, VertexShaderID);
	//glDetachShader(ProgramID, FragmentShaderID);
	
	glDeleteShader(VertexShaderID);
	glDeleteShader(FragmentShaderID);

	return ProgramID;
}

void check_for_shader_compiler() {
    if(!vglHasRuntimeShaderCompiler()) {
        SceMsgDialogParam param;
        sceMsgDialogParamInit(&param);

        SceMsgDialogUserMessageParam user_msg;
        memset(&user_msg, 0, sizeof(SceMsgDialogUserMessageParam));
        user_msg.msg =  "You do not have the runtime shader compiler installed. It must be installed to run this program.\n\n"
                        "Please check the README.md in the repository for a link to instructions on installing it.";
        user_msg.buttonType = SCE_MSG_DIALOG_BUTTON_TYPE_OK;

        param.userMsgParam = &user_msg;
        param.mode = SCE_MSG_DIALOG_MODE_USER_MSG;
        sceMsgDialogInit(&param);

        while (sceMsgDialogGetStatus() != SCE_COMMON_DIALOG_STATUS_FINISHED) {
            vglStartRendering();
            glClear(GL_COLOR_BUFFER_BIT);
            vglStopRenderingInit();
            vglUpdateCommonDialog();
            vglStopRenderingTerm();
        }
        sceKernelExitProcess(0);
    }
}

int main(){
	
	vglEnableRuntimeShaderCompiler(GL_TRUE);
    vglUseVram(GL_TRUE);
    vglWaitVblankStart(GL_TRUE);
	
	
	// Initializing graphics device
	vglInit(0x800000);
	check_for_shader_compiler();
	
	glEnable(GL_DEPTH_TEST);
	
	glClearColor (0.0f, 1.0f, 0.0f, 1.0f);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-1, 1, -1, 1, -1, 1);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	
	GLuint programID = LoadShaders( "app0:vertex.shader", "app0:fragment.shader" );
	
	
	
	for (;;){
		
		
		vglStartRendering();
		glClear(GL_COLOR_BUFFER_BIT);
		
		
		//vglEnableVertexAttribArray(0);
		glEnableClientState(GL_VERTEX_ARRAY);
		glUseProgram(programID);
		//glEnableClientState(GL_COLOR_ARRAY);
		
		glVertexPointer(3, GL_FLOAT, 0, g_vertex_buffer_data);
		//glColorPointer(3, GL_FLOAT, 0, colors);
		
		//glDrawObjects(GL_TRIANGLES, 0, 3);
		
		glDrawArrays(GL_TRIANGLES, 0, 3);
		
		glDisableClientState(GL_COLOR_ARRAY);
		
		vglStopRendering();
		glLoadIdentity();
	}
	
	vglEnd();
	
}

... And here is the shaders:
fragment.shader

float4 main(uniform float4 uClearColor) : COLOR
{
	return float4(0.0, 0.0, 1.0, 1.0);
}

vertex shader

void main(float3 aPosition,
	float4 aColor,
	uniform float4x4 wvp,
	float4 out vPosition : POSITION,
	float4 out vColor : COLOR)
{
	vPosition = float4(aPosition, 1.f);
}

This only gives a white triangle.
With Vita3K I can see they are compiling, but I don´t what is the problem!.

Thanks a lot!

[Rinnegatamante]

Vita3K has no full support for vitaGL at least last time i tried. The white triangle rendering is coming off of a real hw or the emulator?

[carlosbispo]

Hello! Thanks for your reply! I have a white triangle in both vita3k and real hardware...

[Rinnegatamante]

What's the expected rendering? Vertex arrays passed are indeed for a triangle.

[carlosbispo]

According to fragment shader it should appear red. But appears white... Is fragment code wrong?

[Rinnegatamante]

Don't delete the shaders after linking the program. It could produce unexpected behaviours.