Added multi-unbind function to AbstractTexture.

More efficient (no allocation) and also more convenient than calling e.g.
unbind(7, {nullptr, nullptr, nullptr}).

src/Magnum/AbstractTexture.cpp

@@ -151,42 +151,45 @@ void AbstractTexture::unbindImplementationDSA(const GLint textureUnit) {
 }
 #endif
 
+void AbstractTexture::unbind(const Int firstTextureUnit, const std::size_t count) {
+    /* State tracker is updated in the implementations */
+    Context::current()->state().texture->bindMultiImplementation(firstTextureUnit, {nullptr, count});
+}
+
+/** @todoc const std::initializer_list makes Doxygen grumpy */
 void AbstractTexture::bind(const Int firstTextureUnit, std::initializer_list<AbstractTexture*> textures) {
     /* State tracker is updated in the implementations */
-    Context::current()->state().texture->bindMultiImplementation(firstTextureUnit, textures);
+    Context::current()->state().texture->bindMultiImplementation(firstTextureUnit, {textures.begin(), textures.size()});
 }
 
-void AbstractTexture::bindImplementationFallback(const GLint firstTextureUnit, std::initializer_list<AbstractTexture*> textures) {
-    Int unit = firstTextureUnit;
-    for(AbstractTexture* const texture: textures) {
-        if(texture) texture->bind(unit);
-        else unbind(unit);
-        ++unit;
-    }
+void AbstractTexture::bindImplementationFallback(const GLint firstTextureUnit, const Containers::ArrayReference<AbstractTexture* const> textures) {
+    for(std::size_t i = 0; i != textures.size(); ++i)
+        textures && textures[i] ? textures[i]->bind(firstTextureUnit + i) : unbind(firstTextureUnit + i);
 }
 
 #ifndef MAGNUM_TARGET_GLES
-void AbstractTexture::bindImplementationMulti(const GLint firstTextureUnit, std::initializer_list<AbstractTexture*> textures) {
+void AbstractTexture::bindImplementationMulti(const GLint firstTextureUnit, const Containers::ArrayReference<AbstractTexture* const> textures) {
     Implementation::TextureState* const textureState = Context::current()->state().texture;
 
     /* Create array of IDs and also update bindings in state tracker */
-    Containers::Array<GLuint> ids{textures.size()};
-    Int i{};
+    Containers::Array<GLuint> ids{textures ? textures.size() : 0};
     bool different = false;
-    for(AbstractTexture* const texture: textures) {
-        if(texture) texture->createIfNotAlready();
+    for(std::size_t i = 0; i != textures.size(); ++i) {
+        const GLuint id = textures && textures[i] ? textures[i]->_id : 0;
+
+        if(textures) {
+            if(textures[i]) textures[i]->createIfNotAlready();
+            ids[i] = id;
+        }
 
-        const GLuint id = ids[i] = texture ? texture->_id : 0;
         if(textureState->bindings[firstTextureUnit + i].second != id) {
             different = true;
             textureState->bindings[firstTextureUnit + i].second = id;
         }
-
-        ++i;
     }
 
     /* Avoid doing the binding if there is nothing different */
-    if(different) glBindTextures(firstTextureUnit, ids.size(), ids);
+    if(different) glBindTextures(firstTextureUnit, textures.size(), ids);
 }
 #endif
 

src/Magnum/AbstractTexture.h

@@ -203,6 +203,21 @@ class MAGNUM_EXPORT AbstractTexture: public AbstractObject {
          */
         static void unbind(Int textureUnit);
 
+        /**
+         * @brief Unbind textures in given range of texture units
+         *
+         * Unbinds all texture in the range @f$ [ firstTextureUnit ; firstTextureUnit + count ) @f$.
+         * If @extension{ARB,multi_bind} (part of OpenGL 4.4) is not available,
+         * the feature is emulated with sequence of @ref unbind(Int) calls.
+         * @note This function is meant to be used only internally from
+         *      @ref AbstractShaderProgram subclasses. See its documentation
+         *      for more information.
+         * @see @ref Shader::maxCombinedTextureImageUnits(), @fn_gl{BindTextures},
+         *      eventually @fn_gl{ActiveTexture}, @fn_gl{BindTexture} or
+         *      @fn_gl_extension{BindMultiTexture,EXT,direct_state_access}
+         */
+        static void unbind(Int firstTextureUnit, std::size_t count);
+
         /**
          * @brief Bind textures to given range of texture units
          *
@@ -210,12 +225,13 @@ class MAGNUM_EXPORT AbstractTexture: public AbstractObject {
          * `firstTextureUnit + 1` etc. If any texture is `nullptr`, given
          * texture unit is unbound. If @extension{ARB,multi_bind} (part of
          * OpenGL 4.4) is not available, the feature is emulated with sequence
-         * of @ref bind(Int) / @ref unbind() calls.
+         * of @ref bind(Int) / @ref unbind(Int) calls.
          * @note This function is meant to be used only internally from
          *      @ref AbstractShaderProgram subclasses. See its documentation
          *      for more information.
-         * @see @fn_gl{BindTextures}, eventually @fn_gl{ActiveTexture},
-         *      @fn_gl{BindTexture} or @fn_gl_extension{BindMultiTexture,EXT,direct_state_access}
+         * @see @ref Shader::maxCombinedTextureImageUnits(), @fn_gl{BindTextures},
+         *      eventually @fn_gl{ActiveTexture}, @fn_gl{BindTexture} or
+         *      @fn_gl_extension{BindMultiTexture,EXT,direct_state_access}
          */
         static void bind(Int firstTextureUnit, std::initializer_list<AbstractTexture*> textures);
 
@@ -358,9 +374,9 @@ class MAGNUM_EXPORT AbstractTexture: public AbstractObject {
         static void MAGNUM_LOCAL unbindImplementationDSA(GLint textureUnit);
         #endif
 
-        static void MAGNUM_LOCAL bindImplementationFallback(GLint firstTextureUnit, std::initializer_list<AbstractTexture*> textures);
+        static void MAGNUM_LOCAL bindImplementationFallback(GLint firstTextureUnit, Containers::ArrayReference<AbstractTexture* const> textures);
         #ifndef MAGNUM_TARGET_GLES
-        static void MAGNUM_LOCAL bindImplementationMulti(GLint firstTextureUnit, std::initializer_list<AbstractTexture*> textures);
+        static void MAGNUM_LOCAL bindImplementationMulti(GLint firstTextureUnit, Containers::ArrayReference<AbstractTexture* const> textures);
         #endif
 
         void MAGNUM_LOCAL createIfNotAlready();

src/Magnum/Implementation/TextureState.h

@@ -40,7 +40,7 @@ struct TextureState {
     void reset();
 
     void(*unbindImplementation)(GLint);
-    void(*bindMultiImplementation)(GLint, std::initializer_list<AbstractTexture*>);
+    void(*bindMultiImplementation)(GLint, Containers::ArrayReference<AbstractTexture* const>);
     void(AbstractTexture::*bindImplementation)(GLint);
     void(AbstractTexture::*parameteriImplementation)(GLenum, GLint);
     void(AbstractTexture::*parameterfImplementation)(GLenum, GLfloat);

src/Magnum/Test/BufferTextureGLTest.cpp

@@ -78,6 +78,10 @@ void BufferTextureGLTest::bind() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 void BufferTextureGLTest::setBuffer() {

src/Magnum/Test/CubeMapTextureArrayGLTest.cpp

@@ -114,6 +114,10 @@ void CubeMapTextureArrayGLTest::bind() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 void CubeMapTextureArrayGLTest::sampling() {

src/Magnum/Test/CubeMapTextureGLTest.cpp

@@ -139,6 +139,10 @@ void CubeMapTextureGLTest::bind() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 void CubeMapTextureGLTest::sampling() {

src/Magnum/Test/MultisampleTextureGLTest.cpp

@@ -146,6 +146,10 @@ void MultisampleTextureGLTest::bind2D() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 #ifndef MAGNUM_TARGET_GLES
@@ -165,6 +169,10 @@ void MultisampleTextureGLTest::bind2DArray() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 #endif
 

src/Magnum/Test/RectangleTextureGLTest.cpp

@@ -112,6 +112,10 @@ void RectangleTextureGLTest::bind() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 void RectangleTextureGLTest::sampling() {

src/Magnum/Test/TextureArrayGLTest.cpp

@@ -244,6 +244,10 @@ void TextureArrayGLTest::bind1D() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 #endif
 
@@ -265,6 +269,10 @@ void TextureArrayGLTest::bind2D() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 #ifndef MAGNUM_TARGET_GLES

src/Magnum/Test/TextureGLTest.cpp

@@ -303,6 +303,10 @@ void TextureGLTest::bind1D() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 #endif
 
@@ -319,6 +323,10 @@ void TextureGLTest::bind2D() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 void TextureGLTest::bind3D() {
@@ -339,6 +347,10 @@ void TextureGLTest::bind3D() {
     AbstractTexture::bind(7, {&texture, nullptr, &texture});
 
     MAGNUM_VERIFY_NO_ERROR();
+
+    AbstractTexture::unbind(7, 3);
+
+    MAGNUM_VERIFY_NO_ERROR();
 }
 
 #ifndef MAGNUM_TARGET_GLES