nuclear@12: /*
nuclear@12: glviewvol is an OpenGL 3D volume data viewer
nuclear@12: Copyright (C) 2014  John Tsiombikas <nuclear@member.fsf.org>
nuclear@12: 
nuclear@12: This program is free software: you can redistribute it and/or modify
nuclear@12: it under the terms of the GNU General Public License as published by
nuclear@12: the Free Software Foundation, either version 3 of the License, or
nuclear@12: (at your option) any later version.
nuclear@12: 
nuclear@12: This program is distributed in the hope that it will be useful,
nuclear@12: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@12: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@12: GNU General Public License for more details.
nuclear@12: 
nuclear@12: You should have received a copy of the GNU General Public License
nuclear@12: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@12: */
nuclear@4: #include <stdio.h>
nuclear@4: #include <stdlib.h>
nuclear@4: #include <string.h>
nuclear@4: #include <errno.h>
nuclear@4: #include <stdarg.h>
nuclear@4: #include <assert.h>
nuclear@4: #include <GL/glew.h>
nuclear@4: 
nuclear@4: #if defined(unix) || defined(__unix__)
nuclear@4: #include <unistd.h>
nuclear@4: #include <sys/stat.h>
nuclear@4: #endif	/* unix */
nuclear@4: 
nuclear@4: #include "sdr.h"
nuclear@4: 
nuclear@4: static const char *sdrtypestr(unsigned int sdrtype);
nuclear@4: 
nuclear@4: unsigned int create_vertex_shader(const char *src)
nuclear@4: {
nuclear@4: 	return create_shader(src, GL_VERTEX_SHADER);
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int create_pixel_shader(const char *src)
nuclear@4: {
nuclear@4: 	return create_shader(src, GL_FRAGMENT_SHADER);
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int create_tessctl_shader(const char *src)
nuclear@4: {
nuclear@4: #ifdef GL_TESS_CONTROL_SHADER
nuclear@4: 	return create_shader(src, GL_TESS_CONTROL_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int create_tesseval_shader(const char *src)
nuclear@4: {
nuclear@4: #ifdef GL_TESS_EVALUATION_SHADER
nuclear@4: 	return create_shader(src, GL_TESS_EVALUATION_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int create_geometry_shader(const char *src)
nuclear@4: {
nuclear@4: #ifdef GL_GEOMETRY_SHADER
nuclear@4: 	return create_shader(src, GL_GEOMETRY_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int create_shader(const char *src, unsigned int sdr_type)
nuclear@4: {
nuclear@4: 	unsigned int sdr;
nuclear@4: 	int success, info_len;
nuclear@4: 	char *info_str = 0;
nuclear@4: 	GLenum err;
nuclear@4: 
nuclear@4: 	sdr = glCreateShader(sdr_type);
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 	glShaderSource(sdr, 1, &src, 0);
nuclear@4: 	err = glGetError();
nuclear@4: 	assert(err == GL_NO_ERROR);
nuclear@4: 	glCompileShader(sdr);
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 
nuclear@4: 	glGetShaderiv(sdr, GL_COMPILE_STATUS, &success);
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 	glGetShaderiv(sdr, GL_INFO_LOG_LENGTH, &info_len);
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 
nuclear@4: 	if(info_len) {
nuclear@4: 		if((info_str = malloc(info_len + 1))) {
nuclear@4: 			glGetShaderInfoLog(sdr, info_len, 0, info_str);
nuclear@4: 			assert(glGetError() == GL_NO_ERROR);
nuclear@4: 			info_str[info_len] = 0;
nuclear@4: 		}
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	if(success) {
nuclear@4: 		fprintf(stderr, info_str ? "done: %s\n" : "done\n", info_str);
nuclear@4: 	} else {
nuclear@4: 		fprintf(stderr, info_str ? "failed: %s\n" : "failed\n", info_str);
nuclear@4: 		glDeleteShader(sdr);
nuclear@4: 		sdr = 0;
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	free(info_str);
nuclear@4: 	return sdr;
nuclear@4: }
nuclear@4: 
nuclear@4: void free_shader(unsigned int sdr)
nuclear@4: {
nuclear@4: 	glDeleteShader(sdr);
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int load_vertex_shader(const char *fname)
nuclear@4: {
nuclear@4: 	return load_shader(fname, GL_VERTEX_SHADER);
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int load_pixel_shader(const char *fname)
nuclear@4: {
nuclear@4: 	return load_shader(fname, GL_FRAGMENT_SHADER);
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int load_tessctl_shader(const char *fname)
nuclear@4: {
nuclear@4: #ifdef GL_TESS_CONTROL_SHADER
nuclear@4: 	return load_shader(fname, GL_TESS_CONTROL_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int load_tesseval_shader(const char *fname)
nuclear@4: {
nuclear@4: #ifdef GL_TESS_EVALUATION_SHADER
nuclear@4: 	return load_shader(fname, GL_TESS_EVALUATION_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int load_geometry_shader(const char *fname)
nuclear@4: {
nuclear@4: #ifdef GL_GEOMETRY_SHADER
nuclear@4: 	return load_shader(fname, GL_GEOMETRY_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int load_shader(const char *fname, unsigned int sdr_type)
nuclear@4: {
nuclear@4: #if defined(unix) || defined(__unix__)
nuclear@4: 	struct stat st;
nuclear@4: #endif
nuclear@4: 	unsigned int sdr;
nuclear@4: 	size_t filesize;
nuclear@4: 	FILE *fp;
nuclear@4: 	char *src;
nuclear@4: 
nuclear@4: 	if(!(fp = fopen(fname, "rb"))) {
nuclear@4: 		fprintf(stderr, "failed to open shader %s: %s\n", fname, strerror(errno));
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 
nuclear@4: #if defined(unix) || defined(__unix__)
nuclear@4: 	fstat(fileno(fp), &st);
nuclear@4: 	filesize = st.st_size;
nuclear@4: #else
nuclear@4: 	fseek(fp, 0, SEEK_END);
nuclear@4: 	filesize = ftell(fp);
nuclear@4: 	fseek(fp, 0, SEEK_SET);
nuclear@4: #endif	/* unix */
nuclear@4: 
nuclear@4: 	if(!(src = malloc(filesize + 1))) {
nuclear@4: 		fclose(fp);
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 	fread(src, 1, filesize, fp);
nuclear@4: 	src[filesize] = 0;
nuclear@4: 	fclose(fp);
nuclear@4: 
nuclear@4: 	fprintf(stderr, "compiling %s shader: %s... ", sdrtypestr(sdr_type), fname);
nuclear@4: 	sdr = create_shader(src, sdr_type);
nuclear@4: 
nuclear@4: 	free(src);
nuclear@4: 	return sdr;
nuclear@4: }
nuclear@4: 
nuclear@4: 
nuclear@4: unsigned int get_vertex_shader(const char *fname)
nuclear@4: {
nuclear@4: 	return get_shader(fname, GL_VERTEX_SHADER);
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int get_pixel_shader(const char *fname)
nuclear@4: {
nuclear@4: 	return get_shader(fname, GL_FRAGMENT_SHADER);
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int get_tessctl_shader(const char *fname)
nuclear@4: {
nuclear@4: #ifdef GL_TESS_CONTROL_SHADER
nuclear@4: 	return get_shader(fname, GL_TESS_CONTROL_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int get_tesseval_shader(const char *fname)
nuclear@4: {
nuclear@4: #ifdef GL_TESS_EVALUATION_SHADER
nuclear@4: 	return get_shader(fname, GL_TESS_EVALUATION_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int get_geometry_shader(const char *fname)
nuclear@4: {
nuclear@4: #ifdef GL_GEOMETRY_SHADER
nuclear@4: 	return get_shader(fname, GL_GEOMETRY_SHADER);
nuclear@4: #else
nuclear@4: 	return 0;
nuclear@4: #endif
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int get_shader(const char *fname, unsigned int sdr_type)
nuclear@4: {
nuclear@4: 	unsigned int sdr;
nuclear@4: 	if(!(sdr = load_shader(fname, sdr_type))) {
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 	return sdr;
nuclear@4: }
nuclear@4: 
nuclear@4: 
nuclear@4: /* ---- gpu programs ---- */
nuclear@4: 
nuclear@4: unsigned int create_program(void)
nuclear@4: {
nuclear@4: 	unsigned int prog = glCreateProgram();
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 	return prog;
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int create_program_link(unsigned int sdr0, ...)
nuclear@4: {
nuclear@4: 	unsigned int prog, sdr;
nuclear@4: 	va_list ap;
nuclear@4: 
nuclear@4: 	if(!(prog = create_program())) {
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	attach_shader(prog, sdr0);
nuclear@4: 	if(glGetError()) {
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	va_start(ap, sdr0);
nuclear@4: 	while((sdr = va_arg(ap, unsigned int))) {
nuclear@4: 		attach_shader(prog, sdr);
nuclear@4: 		if(glGetError()) {
nuclear@4: 			return 0;
nuclear@4: 		}
nuclear@4: 	}
nuclear@4: 	va_end(ap);
nuclear@4: 
nuclear@4: 	if(link_program(prog) == -1) {
nuclear@4: 		free_program(prog);
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 	return prog;
nuclear@4: }
nuclear@4: 
nuclear@4: unsigned int create_program_load(const char *vfile, const char *pfile)
nuclear@4: {
nuclear@4: 	unsigned int vs = 0, ps = 0;
nuclear@4: 
nuclear@4: 	if(vfile && *vfile && !(vs = get_vertex_shader(vfile))) {
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 	if(pfile && *pfile && !(ps = get_pixel_shader(pfile))) {
nuclear@4: 		return 0;
nuclear@4: 	}
nuclear@4: 	return create_program_link(vs, ps, 0);
nuclear@4: }
nuclear@4: 
nuclear@4: void free_program(unsigned int sdr)
nuclear@4: {
nuclear@4: 	glDeleteProgram(sdr);
nuclear@4: }
nuclear@4: 
nuclear@4: void attach_shader(unsigned int prog, unsigned int sdr)
nuclear@4: {
nuclear@4: 	if(prog && sdr) {
nuclear@4: 		glAttachShader(prog, sdr);
nuclear@4: 		assert(glGetError() == GL_NO_ERROR);
nuclear@4: 	}
nuclear@4: }
nuclear@4: 
nuclear@4: int link_program(unsigned int prog)
nuclear@4: {
nuclear@4: 	int linked, info_len, retval = 0;
nuclear@4: 	char *info_str = 0;
nuclear@4: 
nuclear@4: 	glLinkProgram(prog);
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 	glGetProgramiv(prog, GL_LINK_STATUS, &linked);
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 	glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &info_len);
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: 
nuclear@4: 	if(info_len) {
nuclear@4: 		if((info_str = malloc(info_len + 1))) {
nuclear@4: 			glGetProgramInfoLog(prog, info_len, 0, info_str);
nuclear@4: 			assert(glGetError() == GL_NO_ERROR);
nuclear@4: 			info_str[info_len] = 0;
nuclear@4: 		}
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	if(linked) {
nuclear@4: 		fprintf(stderr, info_str ? "linking done: %s\n" : "linking done\n", info_str);
nuclear@4: 	} else {
nuclear@4: 		fprintf(stderr, info_str ? "linking failed: %s\n" : "linking failed\n", info_str);
nuclear@4: 		retval = -1;
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	free(info_str);
nuclear@4: 	return retval;
nuclear@4: }
nuclear@4: 
nuclear@4: int bind_program(unsigned int prog)
nuclear@4: {
nuclear@4: 	GLenum err;
nuclear@4: 
nuclear@4: 	glUseProgram(prog);
nuclear@4: 	if(prog && (err = glGetError()) != GL_NO_ERROR) {
nuclear@4: 		/* maybe the program is not linked, try linking first */
nuclear@4: 		if(err == GL_INVALID_OPERATION) {
nuclear@4: 			if(link_program(prog) == -1) {
nuclear@4: 				return -1;
nuclear@4: 			}
nuclear@4: 			glUseProgram(prog);
nuclear@4: 			return glGetError() == GL_NO_ERROR ? 0 : -1;
nuclear@4: 		}
nuclear@4: 		return -1;
nuclear@4: 	}
nuclear@4: 	return 0;
nuclear@4: }
nuclear@4: 
nuclear@4: /* ugly but I'm not going to write the same bloody code over and over */
nuclear@4: #define BEGIN_UNIFORM_CODE \
nuclear@4: 	int loc, curr_prog; \
nuclear@4: 	glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog); \
nuclear@4: 	if((unsigned int)curr_prog != prog && bind_program(prog) == -1) { \
nuclear@4: 		return -1; \
nuclear@4: 	} \
nuclear@4: 	if((loc = glGetUniformLocation(prog, name)) != -1)
nuclear@4: 
nuclear@4: #define END_UNIFORM_CODE \
nuclear@4: 	if((unsigned int)curr_prog != prog) { \
nuclear@4: 		bind_program(curr_prog); \
nuclear@4: 	} \
nuclear@4: 	return loc == -1 ? -1 : 0
nuclear@4: 
nuclear@4: int set_uniform_int(unsigned int prog, const char *name, int val)
nuclear@4: {
nuclear@4: 	BEGIN_UNIFORM_CODE {
nuclear@4: 		glUniform1i(loc, val);
nuclear@4: 	}
nuclear@4: 	END_UNIFORM_CODE;
nuclear@4: }
nuclear@4: 
nuclear@4: int set_uniform_float(unsigned int prog, const char *name, float val)
nuclear@4: {
nuclear@4: 	BEGIN_UNIFORM_CODE {
nuclear@4: 		glUniform1f(loc, val);
nuclear@4: 	}
nuclear@4: 	END_UNIFORM_CODE;
nuclear@4: }
nuclear@4: 
nuclear@4: int set_uniform_float2(unsigned int prog, const char *name, float x, float y)
nuclear@4: {
nuclear@4: 	BEGIN_UNIFORM_CODE {
nuclear@4: 		glUniform2f(loc, x, y);
nuclear@4: 	}
nuclear@4: 	END_UNIFORM_CODE;
nuclear@4: }
nuclear@4: 
nuclear@4: int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z)
nuclear@4: {
nuclear@4: 	BEGIN_UNIFORM_CODE {
nuclear@4: 		glUniform3f(loc, x, y, z);
nuclear@4: 	}
nuclear@4: 	END_UNIFORM_CODE;
nuclear@4: }
nuclear@4: 
nuclear@4: int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w)
nuclear@4: {
nuclear@4: 	BEGIN_UNIFORM_CODE {
nuclear@4: 		glUniform4f(loc, x, y, z, w);
nuclear@4: 	}
nuclear@4: 	END_UNIFORM_CODE;
nuclear@4: }
nuclear@4: 
nuclear@4: int set_uniform_matrix4(unsigned int prog, const char *name, float *mat)
nuclear@4: {
nuclear@4: 	BEGIN_UNIFORM_CODE {
nuclear@4: 		glUniformMatrix4fv(loc, 1, GL_FALSE, mat);
nuclear@4: 	}
nuclear@4: 	END_UNIFORM_CODE;
nuclear@4: }
nuclear@4: 
nuclear@4: int set_uniform_matrix4_transposed(unsigned int prog, const char *name, float *mat)
nuclear@4: {
nuclear@4: 	BEGIN_UNIFORM_CODE {
nuclear@4: 		glUniformMatrix4fv(loc, 1, GL_TRUE, mat);
nuclear@4: 	}
nuclear@4: 	END_UNIFORM_CODE;
nuclear@4: }
nuclear@4: 
nuclear@4: int get_attrib_loc(unsigned int prog, const char *name)
nuclear@4: {
nuclear@4: 	int loc, curr_prog;
nuclear@4: 
nuclear@4: 	glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog);
nuclear@4: 	if((unsigned int)curr_prog != prog && bind_program(prog) == -1) {
nuclear@4: 		return -1;
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	loc = glGetAttribLocation(prog, (char*)name);
nuclear@4: 
nuclear@4: 	if((unsigned int)curr_prog != prog) {
nuclear@4: 		bind_program(curr_prog);
nuclear@4: 	}
nuclear@4: 	return loc;
nuclear@4: }
nuclear@4: 
nuclear@4: void set_attrib_float3(int attr_loc, float x, float y, float z)
nuclear@4: {
nuclear@4: 	glVertexAttrib3f(attr_loc, x, y, z);
nuclear@4: }
nuclear@4: 
nuclear@4: static const char *sdrtypestr(unsigned int sdrtype)
nuclear@4: {
nuclear@4: 	switch(sdrtype) {
nuclear@4: 	case GL_VERTEX_SHADER:
nuclear@4: 		return "vertex";
nuclear@4: 	case GL_FRAGMENT_SHADER:
nuclear@4: 		return "pixel";
nuclear@4: #ifdef GL_TESS_CONTROL_SHADER
nuclear@4: 	case GL_TESS_CONTROL_SHADER:
nuclear@4: 		return "tessellation control";
nuclear@4: #endif
nuclear@4: #ifdef GL_TESS_EVALUATION_SHADER
nuclear@4: 	case GL_TESS_EVALUATION_SHADER:
nuclear@4: 		return "tessellation evaluation";
nuclear@4: #endif
nuclear@4: #ifdef GL_GEOMETRY_SHADER
nuclear@4: 	case GL_GEOMETRY_SHADER:
nuclear@4: 		return "geometry";
nuclear@4: #endif
nuclear@4: 
nuclear@4: 	default:
nuclear@4: 		break;
nuclear@4: 	}
nuclear@4: 	return "<unknown>";
nuclear@4: }