From 3d8d7edf6c832b1882ee6aea37339d93b53b66e3 Mon Sep 17 00:00:00 2001
From: Christoph Helma <helma@in-silico.ch>
Date: Thu, 27 Jul 2017 15:47:34 +0200
Subject: single backbuffer

---
 shader.frag | 16 ++++++++++++++--
 sv.c        | 21 +++++++++++++++++++--
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/shader.frag b/shader.frag
index 4741236..c6cc012 100644
--- a/shader.frag
+++ b/shader.frag
@@ -1,4 +1,4 @@
-#version 440 core
+#version 450 core
 #ifdef GL_ES
 precision mediump float;
 #endif
@@ -7,6 +7,8 @@ uniform vec2 resolution;
 uniform float time;
 
 uniform sampler2D images[4];
+layout (binding = 0,rgba32f) uniform image2D backbuffer;
+//uniform image2DArray buffers;
 uniform float ratios[4];
 uniform float params[32];
 
@@ -20,11 +22,21 @@ vec4 image(int i) {
 	vec2 st = gl_FragCoord.xy/resolution.xy;
   st.x *= ratios[i];
   st.x += (1-ratios[i])*0.5;
+  st.x += 0.5*time;
   return texture2D(images[i],st);
 }
 
 void main (void) {
 	vec4 img1 = mix(image(0),image(1),sin(time));
 	vec4 img2 = mix(image(2),image(3),cos(time));
-  fragColor = mix(img1,img2,params[1]);
+  ivec2 P = ivec2(gl_FragCoord.xy);
+  vec4 buf = imageLoad(backbuffer,P);
+  buf.rg = buf.gr;
+  //buf.b = 0.0;
+  vec4 i = mix(img1,img2,0.5);
+  //P = ivec2(gl_FragCoord.xy);
+  imageStore(backbuffer,P,i);
+  i = mix(i,buf,0.8);
+  //i = image(0);
+  fragColor = i;
 }
diff --git a/sv.c b/sv.c
index 461e434..61d6c06 100644
--- a/sv.c
+++ b/sv.c
@@ -17,6 +17,7 @@ GLFWwindow* window;
 GLuint vertex;
 GLuint fragment;
 GLuint shaderProgram;
+GLuint backbuffer;
 int bars;
 
 typedef struct Shad {
@@ -62,6 +63,16 @@ const char * readShader(char * path) {
   return c_str;
 }
 
+/*
+attach_shader(program, GL_VERTEX_SHADER, R"(
+  #version 450 core
+  layout(location=0) in vec2 coord;
+  void main(void) {
+    gl_Position = vec4(coord, 0.0, 1.0);
+  }
+)");
+*/
+
 GLuint compileShader(const char * source, GLenum type) {
   GLuint sh = glCreateShader(type);
   glShaderSource(sh, 1, &source, NULL);
@@ -137,8 +148,10 @@ void readImage(int i) {
   glBindTexture(GL_TEXTURE_2D,images[i].id);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
-  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
+  //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
+  //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
   stbi_image_free(pixels);
 }
@@ -216,6 +229,10 @@ int main(int argc, char **argv) {
     strncpy(images[i-1].path, argv[i],40);
     images[i-1].new = 1;
   }
+  //glActiveTexture(GL_TEXTURE4);
+  glCreateTextures(GL_TEXTURE_2D,1,&backbuffer);
+  glTextureStorage2D(backbuffer,1,GL_RGBA32F,width,height);
+  glBindImageTexture(0,backbuffer, 0, GL_FALSE, 0, GL_READ_WRITE, GL_RGBA32F);
   
   pthread_t stdin_t;
   pthread_create(&stdin_t, NULL, readStdin, NULL);
-- 
cgit v1.2.3