llvertexprogramgl.cpp

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// This file contains the definition of LLVertexProgramGL, 
// for purposes of running vertex programs on GL hardware.

#include "linden_common.h"

#include "llvertexprogramgl.h"

#include "llglheaders.h"

LLVertexProgramGL::LLVertexProgramGL()
{
        mVertexProgramID = 0;
}

LLVertexProgramGL::~LLVertexProgramGL()
{
        glDeleteProgramsARB(1, (GLuint*) &mVertexProgramID);
}

BOOL LLVertexProgramGL::load(const char * filename)
{
        FILE *fp = fopen(filename, "r");
        if (!fp)
        {
                llwarns << "Unable to open vertex program " << filename << llendl;
                return FALSE;
        }

        fseek(fp,0,SEEK_END);
        S32 file_size = ftell(fp);
        fseek(fp,0,SEEK_SET);

        char *text_buffer = new char[file_size + 1];

        S32 num_read = (S32)fread(text_buffer, sizeof(char), file_size, fp);

        if (ferror(fp) || num_read == 0)
        {
                llwarns << "Unable to read vertex program " << filename << llendl;
                fclose(fp);
                delete[] text_buffer;
                return FALSE;
        }
        text_buffer[num_read] = '\0';
        fclose(fp);

        //Send program string to OpenGL
        glGenProgramsARB(1, (GLuint*) &mVertexProgramID);
        glBindProgramARB(GL_VERTEX_PROGRAM_ARB, mVertexProgramID);
        glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB, num_read, text_buffer);

        const GLubyte * program_error_string = glGetString(GL_PROGRAM_ERROR_STRING_ARB);

        GLint error_pos;
        glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &error_pos);

        if(error_pos!=-1)
        {
                glGetError();
                S32 line_num = 1;
                char *next_token = strchr(text_buffer, '\n');
                while(NULL != next_token && next_token < (text_buffer + error_pos))
                {
                        next_token++;
                        line_num++;
                        next_token = strchr(next_token, '\n');
                } 
                char bad_code[11];
                strncpy(bad_code, text_buffer + error_pos, 10);
                bad_code[10] = '\0';

                llerrs << filename << "(" << line_num << "): Vertex Program Error: "
                        << program_error_string << " at (" << bad_code<< ")"
                        << llendl;
                // clean up buffer
                delete[] text_buffer;
                return FALSE;
        }

        // clean up buffer
        delete[] text_buffer;
        return TRUE;
}

void LLVertexProgramGL::bind()
{
        glEnable(GL_VERTEX_PROGRAM_ARB);
        glBindProgramARB(GL_VERTEX_PROGRAM_ARB, mVertexProgramID);
}

void LLVertexProgramGL::unbind()
{
        glDisable(GL_VERTEX_PROGRAM_ARB);
}

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