Cleanup redundant comments

Author: CAMOBAP

app/src/main/cpp/ImageMixer.cpp

@@ -30,15 +30,14 @@ static const char gVertexShader[] =
 static const char gFragmentShader[] =
             "#version 300 es\n"
             "precision mediump float;\n"
-            "uniform vec2 iResolution;\n"
             "uniform sampler2D iChannel0;\n"
             "uniform sampler2D iChannel1;\n"
             "uniform sampler2D iChannel2;\n"
             "uniform sampler2D iChannel3;\n"
             "in vec2 vTexCoord;\n"
             "out vec4 fragmentColor;\n"
             "void main() {\n"
-            "  vec2 uv = vTexCoord; //vec2(vTexCoord.x / 5.0, vTexCoord.y / 5.0);\n"
+            "  vec2 uv = vTexCoord;\n"
             "  vec4 fragColor0 = vec4(texture(iChannel0, uv).rgb, 1.0);\n"
             "  vec4 fragColor1 = vec4(texture(iChannel1, uv).rgb, 1.0);\n"
             "  vec4 fragColor2 = vec4(texture(iChannel2, uv).rgb, 1.0);\n"
@@ -48,33 +47,26 @@ static const char gFragmentShader[] =
 
 ImageMixer::ImageMixer(jni::JNIEnv &env, jni::jint width, jni::jint height)
 {
-    // Step 1 - Get the default display.
     eglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
 
-    // Step 2 - Initialize EGL.
     EGLint eglMajVers, eglMinVers;
     eglInitialize(eglDisplay, &eglMajVers, &eglMinVers);
     LOGI("EGL init with version %d.%d", eglMajVers, eglMinVers);
 
-
-    // Step 3 - Make OpenGL ES the current API.
     eglBindAPI(EGL_OPENGL_ES_API);
 
-    // Step 4 - Specify the required configuration attributes.
     EGLint configAttr[] = {
-            EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,    // very important!
-            EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,          // we will create a pixelbuffer surface
+            EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
+            EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
             EGL_RED_SIZE,   8,
             EGL_GREEN_SIZE, 8,
             EGL_BLUE_SIZE,  8,
             EGL_NONE
     };
 
-    // Step 5 - Find a config that matches all requirements.
     int iConfigs;
     EGLConfig eglConfig;
-    eglChooseConfig(eglDisplay, configAttr, &eglConfig, 1,
-                    &iConfigs);
+    eglChooseConfig(eglDisplay, configAttr, &eglConfig, 1, &iConfigs);
 
     if (iConfigs != 1) {
         jni::ThrowIllegalStateException(env, "Error: eglChooseConfig(): config not found");
@@ -87,16 +79,13 @@ ImageMixer::ImageMixer(jni::JNIEnv &env, jni::jint width, jni::jint height)
     };
     eglSurface = eglCreatePbufferSurface(eglDisplay, eglConfig, surfaceAttr);
 
-    // Step 7 - Create a context.
-
     const EGLint ctxAttr[] = {
-            EGL_CONTEXT_CLIENT_VERSION, 3,              // very important!
+            EGL_CONTEXT_CLIENT_VERSION, 3, // Need to support GLSL 300
             EGL_NONE
     };
-    eglContext = eglCreateContext(eglDisplay, eglConfig, NULL,
+    eglContext = eglCreateContext(eglDisplay, eglConfig, nullptr,
                                   ctxAttr);
 
-    // Step 8 - Bind the context to the current thread
     eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext);
 
     const GLubyte *glslVersion = glGetString(GL_SHADING_LANGUAGE_VERSION);
@@ -108,23 +97,20 @@ ImageMixer::ImageMixer(jni::JNIEnv &env, jni::jint width, jni::jint height)
     if (!glProgram) {
         jni::ThrowIllegalStateException(env, "Could not create program.");
     }
-    gvPositionHandle = glGetAttribLocation(glProgram, "aPosition");
+    glPositionShaderInput = (GLuint)glGetAttribLocation(glProgram, "aPosition");
     checkGlError("glGetAttribLocation");
-    LOGI("glGetAttribLocation(\"aPosition\") = %d\n", gvPositionHandle);
 
     glViewport(0, 0, width, height);
     checkGlError("glViewport");
 
-    glGenBuffers(1, &quadBuffer);
-    glBindBuffer(GL_ARRAY_BUFFER, quadBuffer);
+    glGenBuffers(1, &glQuadBuffer);
+    glBindBuffer(GL_ARRAY_BUFFER, glQuadBuffer);
     glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), quadVertices, GL_STATIC_DRAW);
     glBindBuffer(GL_ARRAY_BUFFER, GL_NONE);
 }
 
 ImageMixer::~ImageMixer()
 {
-    // TODO iterate over textures and unload them all
-
     if (eglDisplay != EGL_NO_DISPLAY) {
         eglMakeCurrent(eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
         if (eglContext != EGL_NO_CONTEXT) {
@@ -181,8 +167,6 @@ void ImageMixer::convert(jni::JNIEnv &env, jni::String &outPath)
     if (!is_egl_context_creator_thread) {
         jni::ThrowIllegalStateException(env, "Called from thread which is different to one who created eglContext");
     }
-    // commit the clear to the offscreen surface
-//    eglSwapBuffers(eglDisplay, eglSurface);
 
     glClearColor(1.0, 1.0, 1.0, 1.0);
     glClear(GL_COLOR_BUFFER_BIT);
@@ -211,35 +195,20 @@ void ImageMixer::convert(jni::JNIEnv &env, jni::String &outPath)
 
         }
     }
-    // bind resolution uniform
-    GLint viewport[4];
 
-    glGetIntegerv(GL_VIEWPORT, viewport);
-    GLsizei width = viewport[2], height = viewport[3];
-    GLint resolutionName = glGetUniformLocation(glProgram, "iResolution");
-    checkGlError("glGetUniformLocation");
-    glUniform2f(resolutionName, (GLfloat)width, (GLfloat)height);
-    checkGlError("glUniform2f");
 
-    glEnableVertexAttribArray(gvPositionHandle);
+    glEnableVertexAttribArray(glPositionShaderInput);
     checkGlError("glEnableVertexAttribArray");
 
-    glBindBuffer(GL_ARRAY_BUFFER, quadBuffer);
+    glBindBuffer(GL_ARRAY_BUFFER, glQuadBuffer);
     checkGlError("glBindBuffer");
-    glVertexAttribPointer(
-            gvPositionHandle,  // attribute
-            2,                  // number of elements per vertex, here (x,y)
-            GL_FLOAT,           // the type of each element
-            GL_FALSE,           // take our values as-is
-            0,                  // no extra data between each position
-            0                   // offset of first element
-    );
+    glVertexAttribPointer(glPositionShaderInput, 2, GL_FLOAT, GL_FALSE, 0, 0);
     checkGlError("glVertexAttribPointer");
 
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     checkGlError("glDrawArrays");
 
-    glDisableVertexAttribArray(gvPositionHandle);
+    glDisableVertexAttribArray(glPositionShaderInput);
     checkGlError("glDisableVertexAttribArray");
 
     for (GLuint unit = 0; unit < MAX_IMAGES; unit++) {
@@ -252,8 +221,9 @@ void ImageMixer::convert(jni::JNIEnv &env, jni::String &outPath)
     }
 
     // read
-
-    const auto readPixels = std::get_temporary_buffer<uint32_t>(width * height);
+    GLint viewport[4];
+    glGetIntegerv(GL_VIEWPORT, viewport);
+    const auto readPixels = std::get_temporary_buffer<uint32_t>(viewport[2] * viewport[3]);
     glReadPixels(viewport[0], viewport[1], viewport[2], viewport[3], GL_RGB, GL_UNSIGNED_BYTE, readPixels.first);
     checkGlError("glReadPixels");
 
@@ -262,7 +232,8 @@ void ImageMixer::convert(jni::JNIEnv &env, jni::String &outPath)
 
     // save
     std::string result_path = jni::Make<std::string>(env, outPath);
-    bool success = (bool) SOIL_save_screenshot(result_path.c_str(), SOIL_SAVE_TYPE_BMP, viewport[0], viewport[1], viewport[2], viewport[3]);
+    int success = SOIL_save_screenshot(result_path.c_str(), SOIL_SAVE_TYPE_BMP,
+            viewport[0], viewport[1], viewport[2], viewport[3]);
     std::return_temporary_buffer(readPixels.first);
 
     if (!success) {

app/src/main/cpp/ImageMixer.hpp

@@ -34,13 +34,9 @@ class ImageMixer final {
     EGLContext eglContext = EGL_NO_CONTEXT;
 
     GLuint glProgram = GL_NONE;
-    GLint gvPositionHandle = GL_NONE;
+    GLuint glPositionShaderInput = GL_NONE;
+    GLuint glQuadBuffer = GL_NONE;
 
-    GLuint quadBuffer = GL_NONE;
-//    GLfloat quadVertices[2*4] { -0.5f, -0.5f,
-//                                +0.5f, -0.5f,
-//                                -0.5f, +0.5f,
-//                                +0.5f, +0.5f };
     GLfloat quadVertices[2*4] { -1, -1,
                                 +1, -1,
                                 -1, +1,