glstuff

commit b5ed7965ca22c482dd6833830969a0082fe3cd8e
parent b5edff414afb811521ed70a23abb524809b07248
Author: Brian Swetland <swetland@frotz.net>
Date:   Sat, 19 Jan 2013 09:42:00 -0800

test4: automatically reload shaders if they've changed on disk

Diffstat:
M
test4.c
 | 
75
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----------------
M
test4.fs
 | 
6
++++--

2 files changed, 62 insertions(+), 19 deletions(-)
diff --git a/test4.c b/test4.c
@@ -20,12 +20,15 @@
 #include "util.h"
 #include "glue.h"
 
+#include <sys/time.h>
+#include <sys/stat.h>
+
 void *texdata;
 unsigned texw, texh;
 
-const char *vert_src, *frag_src;
+char *vert_src, *frag_src;
 
-GLuint pgm, vshd, fshd, tex0;
+GLuint pgm = -1, vshd = -1, fshd = -1, tex0;
 GLuint aVertex, aTexCoord;
 GLuint uMVP, uTexture;
  
@@ -49,15 +52,62 @@ GLfloat texcoords[] = {
 	1.0, 1.0,
 };
 
+time_t vstime = 0, fstime = 0;
+
+void update_shaders(void) {
+	struct stat vsstat, fsstat;
+	GLuint newpgm, newvs, newfs;
+
+	stat("test4.vs", &vsstat);
+	stat("test4.fs", &fsstat);
+
+	if ((vsstat.st_mtime == vstime) && (fsstat.st_mtime == fstime))
+		return;
+
+	vstime = vsstat.st_mtime;
+	fstime = fsstat.st_mtime;
+
+	if (!(vert_src = load_file("test4.vs", 0)))
+		goto exit;
+	if (!(frag_src = load_file("test4.fs", 0)))
+		goto free_vsrc_and_exit;
+
+	if (shader_compile(vert_src, frag_src, &newpgm, &newvs, &newfs))
+		goto free_both_and_exit;
+
+	glDeleteShader(vshd);
+	glDeleteShader(fshd);
+	glDeleteProgram(pgm);
+
+	pgm = newpgm;
+	vshd = newvs;
+	fshd = newfs;
+
+	aVertex = glGetAttribLocation(pgm, "aVertex");
+	aTexCoord = glGetAttribLocation(pgm, "aTexCoord");
+	uMVP = glGetUniformLocation(pgm, "uMVP");
+	uTexture = glGetUniformLocation(pgm, "uTexture");
+
+	free(frag_src);
+	free(vert_src);
+
+	fprintf(stderr,"shaders updated\n");
+	return;
+
+free_both_and_exit:
+	free(frag_src);
+free_vsrc_and_exit:
+	free(vert_src);
+exit:
+	fprintf(stderr,"failed to update shaders\n");
+	return;
+}
+
 int scene_init(struct ctxt *c) {
 	float aspect;
 
 	if (!(texdata = load_png_gray("texture.sdf.png", &texw, &texh, 1)))
 		return -1;
-	if (!(vert_src = load_file("test4.vs", 0)))
-		return -1;
-	if (!(frag_src = load_file("test4.fs", 0)))
-		return -1;
 
  	aspect = ((float)c->width) / ((float)c->height);
 	mtx_ortho(MVP, -aspect, aspect, -1, 1, 1, -1);
@@ -66,20 +116,9 @@ int scene_init(struct ctxt *c) {
 	glClearColor(0, 0, 0, 0);
 	glClearDepth(1.0f);
 
-	if (shader_compile(vert_src, frag_src, &pgm, &vshd, &fshd))
-		return -1;
-
-	aVertex = glGetAttribLocation(pgm, "aVertex");
-	aTexCoord = glGetAttribLocation(pgm, "aTexCoord");
-	uMVP = glGetUniformLocation(pgm, "uMVP");
-	uTexture = glGetUniformLocation(pgm, "uTexture");
-
 	glEnable(GL_TEXTURE_2D);
-//	glEnable(GL_BLEND);
-//	glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
 
 	glGenTextures(1, &tex0);
-	
 	glBindTexture(GL_TEXTURE_2D, tex0);
 	glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, texw, texh, 0, GL_ALPHA,
 		GL_UNSIGNED_BYTE, texdata);
@@ -90,6 +129,8 @@ int scene_init(struct ctxt *c) {
 }
 
 int scene_draw(struct ctxt *c) {
+	update_shaders();
+
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 	glLoadIdentity();
 	glUseProgram(pgm);
diff --git a/test4.fs b/test4.fs
@@ -4,8 +4,10 @@ varying vec2 vTexCoord;
 void main() {
 	float mask = texture2D(uTexture, vTexCoord).a;
 
-	if (mask < 0.5)
+	if (mask < 0.471)
 		discard;
 
-	gl_FragColor = vec4(1, 1, 0, 1);
+	float c = smoothstep(mask, 0.47, 0.49);
+
+	gl_FragColor = vec4(c, c, c, 1);
 }