OpenGL pixel shader: Difference between revisions
Added Go
(Added Kotlin) |
(Added Go) |
||
Line 86:
return 0;
}</lang>
=={{header|Go}}==
{{trans|C}}
{{libheader|FreeGLUT}}
{{libheader|GLEW}}
<br>
The following uses 'cgo' to bind to the above C libraries. As C macro functions cannot be invoked directly from Go code, it has been necessary to wrap them first in 'normal' C functions and then invoke those.
<lang go>package main
/*
#cgo LDFLAGS: -lglut -lGLEW -lGL -lGLU
#include <stdlib.h>
#include <GL/glew.h>
#include <GL/glut.h>
extern void render();
typedef void (*callback) ();
static inline callback idleFunc() {
return render;
}
static inline void glUniform1f_macro(GLint location, GLfloat v0) {
glUniform1f(location, v0);
}
static inline GLuint glCreateShader_macro(GLenum _type) {
return glCreateShader(_type);
}
static inline void glShaderSource_macro(GLuint shader, GLsizei count, const GLchar *const* string, const GLint* length) {
glShaderSource(shader, count, string, length);
}
static inline void glCompileShader_macro(GLuint shader) {
glCompileShader(shader);
}
static inline GLuint glCreateProgram_macro() {
return glCreateProgram();
}
static inline void glAttachShader_macro(GLuint program, GLuint shader) {
glAttachShader(program, shader);
}
static inline void glLinkProgram_macro(GLuint program) {
glLinkProgram(program);
}
static inline void glUseProgram_macro(GLuint program) {
glUseProgram(program);
}
static inline GLint glGetUniformLocation_macro(GLuint program, const GLchar* name) {
return glGetUniformLocation(program, name);
}
*/
import "C"
import "log"
import "unsafe"
var ps, vs, prog, r_mod C.GLuint
var angle = float32(0)
//export render
func render() {
C.glClear(C.GL_COLOR_BUFFER_BIT)
C.glUniform1f_macro(C.GLint(r_mod), C.GLfloat(C.rand())/C.GLfloat(C.RAND_MAX))
C.glLoadIdentity()
C.glRotatef(C.float(angle), C.float(angle*0.1), 1, 0)
C.glBegin(C.GL_TRIANGLES)
C.glVertex3f(-1, -0.5, 0)
C.glVertex3f(0, 1, 0)
C.glVertex3f(1, 0, 0)
C.glEnd()
angle += 0.02
C.glutSwapBuffers()
}
func setShader() {
f := "varying float x, y, z;" +
"uniform float r_mod;" +
"float rand(float s, float r) { return mod(mod(s, r + r_mod) * 112341, 1); }" +
"void main() {" +
" gl_FragColor = vec4(rand(gl_FragCoord.x, x), rand(gl_FragCoord.y, y), rand(gl_FragCoord.z, z), 1);" +
"}"
v := "varying float x, y, z;" +
"void main() {" +
" gl_Position = ftransform();" +
" x = gl_Position.x; y = gl_Position.y; z = gl_Position.z;" +
" x += y; y -= x; z += x - y;" +
"}"
fc, vc := C.CString(f), C.CString(v)
defer C.free(unsafe.Pointer(fc))
defer C.free(unsafe.Pointer(vc))
vs = C.glCreateShader_macro(C.GL_VERTEX_SHADER)
ps = C.glCreateShader_macro(C.GL_FRAGMENT_SHADER)
C.glShaderSource_macro(ps, 1, &fc, nil)
C.glShaderSource_macro(vs, 1, &vc, nil)
C.glCompileShader_macro(vs)
C.glCompileShader_macro(ps)
prog = C.glCreateProgram_macro()
C.glAttachShader_macro(prog, ps)
C.glAttachShader_macro(prog, vs)
C.glLinkProgram_macro(prog)
C.glUseProgram_macro(prog)
rms := C.CString("r_mod")
r_mod = C.GLuint(C.glGetUniformLocation_macro(prog, rms))
C.free(unsafe.Pointer(rms))
}
func main() {
argc := C.int(0)
C.glutInit(&argc, nil)
C.glutInitDisplayMode(C.GLUT_DOUBLE | C.GLUT_RGB)
C.glutInitWindowSize(200, 200)
tl := "Pixel Shader"
tlc := C.CString(tl)
C.glutCreateWindow(tlc)
defer C.free(unsafe.Pointer(tlc))
C.glutIdleFunc(C.idleFunc())
C.glewInit()
glv := C.CString("GL_VERSION_2_0")
if C.glewIsSupported(glv) == 0 {
log.Fatal("GL 2.0 unsupported")
}
defer C.free(unsafe.Pointer(glv))
setShader()
C.glutMainLoop()
}</lang>
| |||