# HG changeset patch
# User Sebastien Jodogne <s.jodogne@gmail.com>
# Date 1683191179 -7200
# Node ID 4e31d76c7ecd069a2e54c32725d0abdcf55afe1d
# Parent  b6b5e1ca1cc2174c92ff0cec4c6b66ed4e61d88e
making ImageProcessingProgram compatible with 3D volumes

diff -r b6b5e1ca1cc2 -r 4e31d76c7ecd OrthancStone/Sources/OpenGL/ImageProcessingProgram.cpp
--- a/OrthancStone/Sources/OpenGL/ImageProcessingProgram.cpp	Wed May 03 22:00:38 2023 +0200
+++ b/OrthancStone/Sources/OpenGL/ImageProcessingProgram.cpp	Thu May 04 11:06:19 2023 +0200
@@ -50,7 +50,7 @@
  * "a_position" (position in the target frame buffer) ranges from -1
  * to 1, whereas texture samplers range from 0 to 1.
  **/
-static const char* VERTEX_SHADER =
+static const char* VERTEX_SHADER_2D =
   "in vec2 a_position;                        \n"
   "out vec2 v_position;                       \n"
   "void main() {                              \n"
@@ -59,6 +59,21 @@
   "}                                          \n";
 
 
+/**
+ * VERTEX_SHADER_3D allows to sample a 3D texture by introducing the
+ * "u_z" uniform whose range is in [0,1] and that allows to scan a 3D
+ * texture along its Z axis.
+ **/
+static const char* VERTEX_SHADER_3D =
+  "in vec2 a_position;                                 \n"
+  "out vec3 v_position;                                \n"
+  "uniform float u_z;                                  \n"
+  "void main() {                                       \n"
+  "  v_position = vec3((a_position + 1.0) / 2.0, u_z); \n"
+  "  gl_Position = vec4(a_position, u_z, 1.0);         \n"
+  "}                                                   \n";
+
+
 namespace OrthancStone
 {
   namespace OpenGL
@@ -74,7 +89,8 @@
 
 
     ImageProcessingProgram::ImageProcessingProgram(IOpenGLContext& context,
-                                                   const std::string& fragmentShader) :
+                                                   const std::string& fragmentShader,
+                                                   bool addUniformZ) :
       program_(context),
       quad_vertexbuffer(0)
     {
@@ -103,7 +119,8 @@
       version = ("#version 300 es\n"
                  "precision highp float;\n"
                  "precision highp sampler2D;\n"
-                 "precision highp sampler2DArray;\n");
+                 "precision highp sampler2DArray;\n"
+                 "precision highp sampler3D;\n");
 #else
       /**
        * "#version 130" corresponds to:
@@ -113,7 +130,18 @@
       version = "#version 130\n";
 #endif
 
-      program_.CompileShaders(version + VERTEX_SHADER, version + fragmentShader);
+      std::string vertexShader;
+
+      if (addUniformZ)
+      {
+        vertexShader = version + VERTEX_SHADER_3D;
+      }
+      else
+      {
+        vertexShader = version + VERTEX_SHADER_2D;
+      }
+      
+      program_.CompileShaders(vertexShader, version + fragmentShader);
 
       glGenBuffers(1, &quad_vertexbuffer);
       if (quad_vertexbuffer == 0)
diff -r b6b5e1ca1cc2 -r 4e31d76c7ecd OrthancStone/Sources/OpenGL/ImageProcessingProgram.h
--- a/OrthancStone/Sources/OpenGL/ImageProcessingProgram.h	Wed May 03 22:00:38 2023 +0200
+++ b/OrthancStone/Sources/OpenGL/ImageProcessingProgram.h	Thu May 04 11:06:19 2023 +0200
@@ -33,6 +33,7 @@
     class OpenGLFramebuffer;
     class OpenGLTexture;
     class OpenGLTextureArray;
+    class OpenGLTextureVolume;
 
     class ImageProcessingProgram : public boost::noncopyable
     {
@@ -44,7 +45,8 @@
 
     public:
       ImageProcessingProgram(IOpenGLContext& context,
-                             const std::string& fragmentShader);
+                             const std::string& fragmentShader,
+                             bool addUniformZ /* for 3D texture sampling */);
 
       ~ImageProcessingProgram();
 
@@ -57,6 +59,11 @@
                OpenGLFramebuffer& framebuffer,
                bool checkStatus);
 
+      void Use(OpenGLTextureVolume& volume,
+               unsigned int z,
+               OpenGLFramebuffer& framebuffer,
+               bool checkStatus);
+
       void Render();
 
       GLint GetUniformLocation(const std::string& name)
diff -r b6b5e1ca1cc2 -r 4e31d76c7ecd OrthancStone/Sources/OpenGL/OpenGLFramebuffer.cpp
--- a/OrthancStone/Sources/OpenGL/OpenGLFramebuffer.cpp	Wed May 03 22:00:38 2023 +0200
+++ b/OrthancStone/Sources/OpenGL/OpenGLFramebuffer.cpp	Thu May 04 11:06:19 2023 +0200
@@ -191,6 +191,8 @@
     void OpenGLFramebuffer::SetTarget(OpenGLTexture& target)
     {
       glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, target.GetId(), 0);
+      ORTHANC_OPENGL_CHECK("glFramebufferTexture2D()");
+
       SetupTextureTarget();
       glViewport(0, 0, target.GetWidth(), target.GetHeight());
     }
@@ -206,6 +208,8 @@
       else
       {
         glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, target.GetId(), 0, layer);
+        ORTHANC_OPENGL_CHECK("glFramebufferTextureLayer()");
+
         SetupTextureTarget();
         glViewport(0, 0, target.GetWidth(), target.GetHeight());
       }