xerebus: average samples in shader
authorJohn Tsiombikas <nuclear@member.fsf.org>
Wed, 23 Dec 2020 03:17:02 +0000 (05:17 +0200)
committerJohn Tsiombikas <nuclear@member.fsf.org>
Wed, 23 Dec 2020 03:17:02 +0000 (05:17 +0200)
xerebus/src/main.c
xerebus/src/opengl.h [new file with mode: 0644]
xerebus/src/sdr.c [new file with mode: 0644]
xerebus/src/sdr.h [new file with mode: 0644]

index e7c0728..7f288ab 100644 (file)
@@ -1,6 +1,8 @@
 #include <stdio.h>
+#include "opengl.h"
 #include "miniglut.h"
 #include "erebus.h"
+#include "sdr.h"
 
 static void display(void);
 static void reshape(int x, int y);
@@ -18,10 +20,34 @@ static int mouse_x, mouse_y;
 static int drag_x, drag_y;
 static int drag;
 
+static float disp_gamma = 2.2f;
+
 static unsigned int fbtex;
+static unsigned int sdr;
+
+static const char *vs_src =
+       "void main()\n"
+       "{\n"
+       "       gl_Position = ftransform();\n"
+       "       gl_TexCoord[0] = gl_MultiTexCoord0;\n"
+       "}\n";
+
+static const char *ps_src =
+       "uniform sampler2D tex;\n"
+       "uniform float inv_gamma;\n"
+       "\n"
+       "void main()\n"
+       "{\n"
+       "       vec4 texel = texture2D(tex, gl_TexCoord[0].st);\n"
+       "       gl_FragColor.rgb = pow(texel.xyz / texel.w, vec3(inv_gamma));\n"
+       "       gl_FragColor.a = 1.0;\n"
+       "}\n";
+
 
 int main(int argc, char **argv)
 {
+       unsigned int vs, ps;
+
        glutInit(&argc, argv);
        glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
        glutInitWindowSize(1280, 800);
@@ -33,6 +59,17 @@ int main(int argc, char **argv)
        glutMouseFunc(mouse);
        glutMotionFunc(motion);
 
+       if(!(vs = create_vertex_shader(vs_src))) {
+               return 1;
+       }
+       if(!(ps = create_pixel_shader(ps_src))) {
+               return 1;
+       }
+       if(!(sdr = create_program_link(vs, ps, 0))) {
+               return 1;
+       }
+       set_uniform_float(sdr, "inv_gamma", 1.0f / disp_gamma);
+
        if(!(erb = erb_create())) {
                return 1;
        }
@@ -42,7 +79,6 @@ int main(int argc, char **argv)
        glBindTexture(GL_TEXTURE_2D, fbtex);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-       glEnable(GL_TEXTURE_2D);
 
        glutMainLoop();
        erb_destroy(erb);
@@ -68,6 +104,8 @@ static void display(void)
 
        glClear(GL_COLOR_BUFFER_BIT);
 
+       glUseProgram(sdr);
+
        glBegin(GL_QUADS);
        glColor3f(1, 1, 1);
        glTexCoord2f(0, 0);
@@ -81,8 +119,8 @@ static void display(void)
        glEnd();
 
        if(drag) {
-               glPushAttrib(GL_ENABLE_BIT);
-               glDisable(GL_TEXTURE_2D);
+               glUseProgram(0);
+
                glEnable(GL_LOGIC_OP);
                glLogicOp(GL_XOR);
 
@@ -94,7 +132,7 @@ static void display(void)
                glVertex2f(drag_x, mouse_y);
                glEnd();
 
-               glPopAttrib();
+               glDisable(GL_LOGIC_OP);
        }
 
        glutSwapBuffers();
diff --git a/xerebus/src/opengl.h b/xerebus/src/opengl.h
new file mode 100644 (file)
index 0000000..c201273
--- /dev/null
@@ -0,0 +1,8 @@
+#ifndef OPENGL_H_
+#define OPENGL_H_
+
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glext.h>
+
+#endif /* OPENGL_H_ */
diff --git a/xerebus/src/sdr.c b/xerebus/src/sdr.c
new file mode 100644 (file)
index 0000000..0152a6e
--- /dev/null
@@ -0,0 +1,562 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <assert.h>
+#include "opengl.h"
+
+#if defined(unix) || defined(__unix__)
+#include <unistd.h>
+#include <sys/stat.h>
+#endif /* unix */
+
+#include "sdr.h"
+
+static const char *sdrtypestr(unsigned int sdrtype);
+static int sdrtypeidx(unsigned int sdrtype);
+
+
+unsigned int create_vertex_shader(const char *src)
+{
+       return create_shader(src, GL_VERTEX_SHADER);
+}
+
+unsigned int create_pixel_shader(const char *src)
+{
+       return create_shader(src, GL_FRAGMENT_SHADER);
+}
+
+unsigned int create_tessctl_shader(const char *src)
+{
+#ifdef GL_TESS_CONTROL_SHADER
+       return create_shader(src, GL_TESS_CONTROL_SHADER);
+#else
+       return 0;
+#endif
+}
+
+unsigned int create_tesseval_shader(const char *src)
+{
+#ifdef GL_TESS_EVALUATION_SHADER
+       return create_shader(src, GL_TESS_EVALUATION_SHADER);
+#else
+       return 0;
+#endif
+}
+
+unsigned int create_geometry_shader(const char *src)
+{
+#ifdef GL_GEOMETRY_SHADER
+       return create_shader(src, GL_GEOMETRY_SHADER);
+#else
+       return 0;
+#endif
+}
+
+unsigned int create_shader(const char *src, unsigned int sdr_type)
+{
+       unsigned int sdr;
+       int success, info_len;
+       char *info_str = 0;
+       const char *src_str[3], *header, *footer;
+       int src_str_count = 0;
+       GLenum err;
+
+       if((header = get_shader_header(sdr_type))) {
+               src_str[src_str_count++] = header;
+       }
+       src_str[src_str_count++] = src;
+       if((footer = get_shader_footer(sdr_type))) {
+               src_str[src_str_count++] = footer;
+       }
+
+       sdr = glCreateShader(sdr_type);
+       assert(glGetError() == GL_NO_ERROR);
+       glShaderSource(sdr, src_str_count, src_str, 0);
+       err = glGetError();
+       assert(err == GL_NO_ERROR);
+       glCompileShader(sdr);
+       assert(glGetError() == GL_NO_ERROR);
+
+       glGetShaderiv(sdr, GL_COMPILE_STATUS, &success);
+       assert(glGetError() == GL_NO_ERROR);
+       glGetShaderiv(sdr, GL_INFO_LOG_LENGTH, &info_len);
+       assert(glGetError() == GL_NO_ERROR);
+
+       if(info_len) {
+               if((info_str = malloc(info_len + 1))) {
+                       glGetShaderInfoLog(sdr, info_len, 0, info_str);
+                       assert(glGetError() == GL_NO_ERROR);
+                       info_str[info_len] = 0;
+               }
+       }
+
+       if(success) {
+               fprintf(stderr, info_str ? "done: %s\n" : "done\n", info_str);
+       } else {
+               fprintf(stderr, info_str ? "failed: %s\n" : "failed\n", info_str);
+               glDeleteShader(sdr);
+               sdr = 0;
+       }
+
+       free(info_str);
+       return sdr;
+}
+
+void free_shader(unsigned int sdr)
+{
+       glDeleteShader(sdr);
+}
+
+unsigned int load_vertex_shader(const char *fname)
+{
+       return load_shader(fname, GL_VERTEX_SHADER);
+}
+
+unsigned int load_pixel_shader(const char *fname)
+{
+       return load_shader(fname, GL_FRAGMENT_SHADER);
+}
+
+unsigned int load_tessctl_shader(const char *fname)
+{
+#ifdef GL_TESS_CONTROL_SHADER
+       return load_shader(fname, GL_TESS_CONTROL_SHADER);
+#else
+       return 0;
+#endif
+}
+
+unsigned int load_tesseval_shader(const char *fname)
+{
+#ifdef GL_TESS_EVALUATION_SHADER
+       return load_shader(fname, GL_TESS_EVALUATION_SHADER);
+#else
+       return 0;
+#endif
+}
+
+unsigned int load_geometry_shader(const char *fname)
+{
+#ifdef GL_GEOMETRY_SHADER
+       return load_shader(fname, GL_GEOMETRY_SHADER);
+#else
+       return 0;
+#endif
+}
+
+unsigned int load_shader(const char *fname, unsigned int sdr_type)
+{
+       unsigned int sdr;
+       size_t filesize;
+       FILE *fp;
+       char *src;
+
+       if(!(fp = fopen(fname, "rb"))) {
+               fprintf(stderr, "failed to open shader %s: %s\n", fname, strerror(errno));
+               return 0;
+       }
+
+       fseek(fp, 0, SEEK_END);
+       filesize = ftell(fp);
+       fseek(fp, 0, SEEK_SET);
+
+       if(!(src = malloc(filesize + 1))) {
+               fclose(fp);
+               return 0;
+       }
+       fread(src, 1, filesize, fp);
+       src[filesize] = 0;
+       fclose(fp);
+
+       fprintf(stderr, "compiling %s shader: %s... ", sdrtypestr(sdr_type), fname);
+       sdr = create_shader(src, sdr_type);
+
+       free(src);
+       return sdr;
+}
+
+
+/* ---- gpu programs ---- */
+
+unsigned int create_program(void)
+{
+       unsigned int prog = glCreateProgram();
+       assert(glGetError() == GL_NO_ERROR);
+       return prog;
+}
+
+unsigned int create_program_link(unsigned int sdr0, ...)
+{
+       unsigned int prog, sdr;
+       va_list ap;
+
+       if(!(prog = create_program())) {
+               return 0;
+       }
+
+       attach_shader(prog, sdr0);
+       if(glGetError()) {
+               return 0;
+       }
+
+       va_start(ap, sdr0);
+       while((sdr = va_arg(ap, unsigned int))) {
+               attach_shader(prog, sdr);
+               if(glGetError()) {
+                       return 0;
+               }
+       }
+       va_end(ap);
+
+       if(link_program(prog) == -1) {
+               free_program(prog);
+               return 0;
+       }
+       return prog;
+}
+
+unsigned int create_program_load(const char *vfile, const char *pfile)
+{
+       unsigned int vs = 0, ps = 0;
+
+       if(vfile && *vfile && !(vs = load_vertex_shader(vfile))) {
+               return 0;
+       }
+       if(pfile && *pfile && !(ps = load_pixel_shader(pfile))) {
+               return 0;
+       }
+       return create_program_link(vs, ps, 0);
+}
+
+void free_program(unsigned int sdr)
+{
+       glDeleteProgram(sdr);
+}
+
+void attach_shader(unsigned int prog, unsigned int sdr)
+{
+       int err;
+
+       if(prog && sdr) {
+               assert(glGetError() == GL_NO_ERROR);
+               glAttachShader(prog, sdr);
+               if((err = glGetError()) != GL_NO_ERROR) {
+                       fprintf(stderr, "failed to attach shader %u to program %u (err: 0x%x)\n", sdr, prog, err);
+                       abort();
+               }
+       }
+}
+
+int link_program(unsigned int prog)
+{
+       int linked, info_len, retval = 0;
+       char *info_str = 0;
+
+       glLinkProgram(prog);
+       assert(glGetError() == GL_NO_ERROR);
+       glGetProgramiv(prog, GL_LINK_STATUS, &linked);
+       assert(glGetError() == GL_NO_ERROR);
+       glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &info_len);
+       assert(glGetError() == GL_NO_ERROR);
+
+       if(info_len) {
+               if((info_str = malloc(info_len + 1))) {
+                       glGetProgramInfoLog(prog, info_len, 0, info_str);
+                       assert(glGetError() == GL_NO_ERROR);
+                       info_str[info_len] = 0;
+               }
+       }
+
+       if(linked) {
+               fprintf(stderr, info_str ? "linking done: %s\n" : "linking done\n", info_str);
+       } else {
+               fprintf(stderr, info_str ? "linking failed: %s\n" : "linking failed\n", info_str);
+               retval = -1;
+       }
+
+       free(info_str);
+       return retval;
+}
+
+int bind_program(unsigned int prog)
+{
+       GLenum err;
+
+       glUseProgram(prog);
+       if(prog && (err = glGetError()) != GL_NO_ERROR) {
+               /* maybe the program is not linked, try linking first */
+               if(err == GL_INVALID_OPERATION) {
+                       if(link_program(prog) == -1) {
+                               return -1;
+                       }
+                       glUseProgram(prog);
+                       return glGetError() == GL_NO_ERROR ? 0 : -1;
+               }
+               return -1;
+       }
+       return 0;
+}
+
+/* ugly but I'm not going to write the same bloody code over and over */
+#define BEGIN_UNIFORM_CODE \
+       int loc, curr_prog; \
+       glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog); \
+       if((unsigned int)curr_prog != prog && bind_program(prog) == -1) { \
+               return -1; \
+       } \
+       if((loc = glGetUniformLocation(prog, name)) != -1)
+
+#define END_UNIFORM_CODE \
+       if((unsigned int)curr_prog != prog) { \
+               bind_program(curr_prog); \
+       } \
+       return loc == -1 ? -1 : 0
+
+int get_uniform_loc(unsigned int prog, const char *name)
+{
+       int loc, curr_prog;
+       glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog);
+       if((unsigned int)curr_prog != prog && bind_program(prog) == -1) {
+               return -1;
+       }
+       loc = glGetUniformLocation(prog, name);
+       if((unsigned int)curr_prog != prog) {
+               bind_program(curr_prog);
+       }
+       return loc;
+}
+
+int set_uniform_int(unsigned int prog, const char *name, int val)
+{
+       BEGIN_UNIFORM_CODE {
+               glUniform1i(loc, val);
+       }
+       END_UNIFORM_CODE;
+}
+
+int set_uniform_float(unsigned int prog, const char *name, float val)
+{
+       BEGIN_UNIFORM_CODE {
+               glUniform1f(loc, val);
+       }
+       END_UNIFORM_CODE;
+}
+
+int set_uniform_float2(unsigned int prog, const char *name, float x, float y)
+{
+       BEGIN_UNIFORM_CODE {
+               glUniform2f(loc, x, y);
+       }
+       END_UNIFORM_CODE;
+}
+
+int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z)
+{
+       BEGIN_UNIFORM_CODE {
+               glUniform3f(loc, x, y, z);
+       }
+       END_UNIFORM_CODE;
+}
+
+int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w)
+{
+       BEGIN_UNIFORM_CODE {
+               glUniform4f(loc, x, y, z, w);
+       }
+       END_UNIFORM_CODE;
+}
+
+int set_uniform_matrix4(unsigned int prog, const char *name, const float *mat)
+{
+       BEGIN_UNIFORM_CODE {
+               glUniformMatrix4fv(loc, 1, GL_FALSE, mat);
+       }
+       END_UNIFORM_CODE;
+}
+
+int set_uniform_matrix4_transposed(unsigned int prog, const char *name, const float *mat)
+{
+       BEGIN_UNIFORM_CODE {
+               glUniformMatrix4fv(loc, 1, GL_TRUE, mat);
+       }
+       END_UNIFORM_CODE;
+}
+
+int get_attrib_loc(unsigned int prog, const char *name)
+{
+       int loc, curr_prog;
+
+       glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog);
+       if((unsigned int)curr_prog != prog && bind_program(prog) == -1) {
+               return -1;
+       }
+
+       loc = glGetAttribLocation(prog, (char*)name);
+
+       if((unsigned int)curr_prog != prog) {
+               bind_program(curr_prog);
+       }
+       return loc;
+}
+
+void set_attrib_float3(int attr_loc, float x, float y, float z)
+{
+       glVertexAttrib3f(attr_loc, x, y, z);
+}
+
+/* ---- shader composition ---- */
+struct string {
+       char *text;
+       int len;
+};
+
+#define NUM_SHADER_TYPES       5
+static struct string header[NUM_SHADER_TYPES];
+static struct string footer[NUM_SHADER_TYPES];
+
+static void clear_string(struct string *str)
+{
+       free(str->text);
+       str->text = 0;
+       str->len = 0;
+}
+
+static void append_string(struct string *str, const char *s)
+{
+       int len, newlen;
+       char *newstr;
+
+       if(!s || !*s) return;
+
+       len = strlen(s);
+       newlen = str->len + len;
+       if(!(newstr = malloc(newlen + 2))) {    /* leave space for a possible newline */
+               fprintf(stderr, "shader composition: failed to append string of size %d\n", len);
+               abort();
+       }
+
+       if(str->text) {
+               memcpy(newstr, str->text, str->len);
+       }
+       memcpy(newstr + str->len, s, len + 1);
+
+       if(s[len - 1] != '\n') {
+               newstr[newlen] = '\n';
+               newstr[newlen + 1] = 0;
+       }
+
+       free(str->text);
+       str->text = newstr;
+       str->len = newlen;
+}
+
+void clear_shader_header(unsigned int type)
+{
+       if(type) {
+               int idx = sdrtypeidx(type);
+               clear_string(&header[idx]);
+       } else {
+               int i;
+               for(i=0; i<NUM_SHADER_TYPES; i++) {
+                       clear_string(&header[i]);
+               }
+       }
+}
+
+void clear_shader_footer(unsigned int type)
+{
+       if(type) {
+               int idx = sdrtypeidx(type);
+               clear_string(&footer[idx]);
+       } else {
+               int i;
+               for(i=0; i<NUM_SHADER_TYPES; i++) {
+                       clear_string(&footer[i]);
+               }
+       }
+}
+
+void add_shader_header(unsigned int type, const char *s)
+{
+       if(type) {
+               int idx = sdrtypeidx(type);
+               append_string(&header[idx], s);
+       } else {
+               int i;
+               for(i=0; i<NUM_SHADER_TYPES; i++) {
+                       append_string(&header[i], s);
+               }
+       }
+}
+
+void add_shader_footer(unsigned int type, const char *s)
+{
+       if(type) {
+               int idx = sdrtypeidx(type);
+               append_string(&footer[idx], s);
+       } else {
+               int i;
+               for(i=0; i<NUM_SHADER_TYPES; i++) {
+                       append_string(&footer[i], s);
+               }
+       }
+}
+
+const char *get_shader_header(unsigned int type)
+{
+       int idx = sdrtypeidx(type);
+       return header[idx].text;
+}
+
+const char *get_shader_footer(unsigned int type)
+{
+       int idx = sdrtypeidx(type);
+       return footer[idx].text;
+}
+
+static const char *sdrtypestr(unsigned int sdrtype)
+{
+       switch(sdrtype) {
+       case GL_VERTEX_SHADER:
+               return "vertex";
+       case GL_FRAGMENT_SHADER:
+               return "pixel";
+#ifdef GL_TESS_CONTROL_SHADER
+       case GL_TESS_CONTROL_SHADER:
+               return "tessellation control";
+#endif
+#ifdef GL_TESS_EVALUATION_SHADER
+       case GL_TESS_EVALUATION_SHADER:
+               return "tessellation evaluation";
+#endif
+#ifdef GL_GEOMETRY_SHADER
+       case GL_GEOMETRY_SHADER:
+               return "geometry";
+#endif
+
+       default:
+               break;
+       }
+       return "<unknown>";
+}
+
+static int sdrtypeidx(unsigned int sdrtype)
+{
+       switch(sdrtype) {
+       case GL_VERTEX_SHADER:
+               return 0;
+       case GL_FRAGMENT_SHADER:
+               return 1;
+       case GL_TESS_CONTROL_SHADER:
+               return 2;
+       case GL_TESS_EVALUATION_SHADER:
+               return 3;
+       case GL_GEOMETRY_SHADER:
+               return 4;
+       default:
+               break;
+       }
+       return 0;
+}
diff --git a/xerebus/src/sdr.h b/xerebus/src/sdr.h
new file mode 100644 (file)
index 0000000..7bf2389
--- /dev/null
@@ -0,0 +1,68 @@
+#ifndef SDR_H_
+#define SDR_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* ---- shaders ---- */
+unsigned int create_vertex_shader(const char *src);
+unsigned int create_pixel_shader(const char *src);
+unsigned int create_tessctl_shader(const char *src);
+unsigned int create_tesseval_shader(const char *src);
+unsigned int create_geometry_shader(const char *src);
+unsigned int create_shader(const char *src, unsigned int sdr_type);
+void free_shader(unsigned int sdr);
+
+unsigned int load_vertex_shader(const char *fname);
+unsigned int load_pixel_shader(const char *fname);
+unsigned int load_tessctl_shader(const char *fname);
+unsigned int load_tesseval_shader(const char *fname);
+unsigned int load_geometry_shader(const char *fname);
+unsigned int load_shader(const char *src, unsigned int sdr_type);
+
+int add_shader(const char *fname, unsigned int sdr);
+int remove_shader(const char *fname);
+
+/* ---- gpu programs ---- */
+unsigned int create_program(void);
+unsigned int create_program_link(unsigned int sdr0, ...);
+unsigned int create_program_load(const char *vfile, const char *pfile);
+void free_program(unsigned int sdr);
+
+void attach_shader(unsigned int prog, unsigned int sdr);
+int link_program(unsigned int prog);
+int bind_program(unsigned int prog);
+
+int get_uniform_loc(unsigned int prog, const char *name);
+
+int set_uniform_int(unsigned int prog, const char *name, int val);
+int set_uniform_float(unsigned int prog, const char *name, float val);
+int set_uniform_float2(unsigned int prog, const char *name, float x, float y);
+int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z);
+int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w);
+int set_uniform_matrix4(unsigned int prog, const char *name, const float *mat);
+int set_uniform_matrix4_transposed(unsigned int prog, const char *name, const float *mat);
+
+int get_attrib_loc(unsigned int prog, const char *name);
+void set_attrib_float3(int attr_loc, float x, float y, float z);
+
+/* ---- shader composition ---- */
+
+/* clear shader header/footer text.
+ * pass the shader type to clear, or 0 to clear all types */
+void clear_shader_header(unsigned int type);
+void clear_shader_footer(unsigned int type);
+/* append text to the header/footer of a specific shader type
+ * or use type 0 to add it to all shade types */
+void add_shader_header(unsigned int type, const char *s);
+void add_shader_footer(unsigned int type, const char *s);
+/* get the current header/footer text for a specific shader type */
+const char *get_shader_header(unsigned int type);
+const char *get_shader_footer(unsigned int type);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* SDR_H_ */