GLES fixes

resources/imageview_fragment.gles

@@ -0,0 +1,17 @@
+precision highp float;
+
+varying vec2 uv;
+varying vec2 position_background;
+uniform sampler2D image;
+uniform vec4 background_color;
+
+void main() {
+    vec2 frac = position_background - floor(position_background);
+    float checkerboard = ((frac.x > .5) == (frac.y > .5)) ? 0.4 : 0.5;
+
+    vec4 background = (1.0 - background_color.a) * vec4(vec3(checkerboard), 1.0) +
+                             background_color.a * vec4(background_color.rgb, 1.0);
+
+    vec4 value = texture2D(image, uv);
+    gl_FragColor = (1.0 - value.a) * background + value.a * vec4(value.rgb, 1.0);
+}

resources/imageview_vertex.gles

@@ -0,0 +1,14 @@
+precision highp float;
+
+uniform mat4 matrix_image;
+uniform mat4 matrix_background;
+attribute vec2 position;
+varying vec2 position_background;
+varying vec2 uv;
+
+void main() {
+    vec4 p = vec4(position, 0.0, 1.0);
+    gl_Position = matrix_image * p;
+    position_background = (matrix_background * p).xy;
+    uv = position;
+}

src/example1.cpp

@@ -577,14 +577,16 @@ int main(int /* argc */, char ** /* argv */) {
         }
 
         nanogui::shutdown();
-    } catch (const std::runtime_error &e) {
+    } catch (const std::exception &e) {
         std::string error_msg = std::string("Caught a fatal error: ") + std::string(e.what());
         #if defined(_WIN32)
             MessageBoxA(nullptr, error_msg.c_str(), NULL, MB_ICONERROR | MB_OK);
         #else
             std::cerr << error_msg << std::endl;
         #endif
         return -1;
+    } catch (...) {
+        std::cerr << "Caught an unknown error!" << std::endl;
     }
 
     return 0;

src/shader_gl.cpp

@@ -248,9 +248,9 @@ Shader::Shader(RenderPass *render_pass,
 
 #if defined(NANOGUI_USE_OPENGL)
     CHK(glGenVertexArrays(1, &m_vertex_array_handle));
-#endif
 
     m_uses_point_size = vertex_shader.find("gl_PointSize") != std::string::npos;
+#endif
 }
 
 Shader::~Shader() {
@@ -511,16 +511,18 @@ void Shader::begin() {
         CHK(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
     }
 
+#if defined(NANOGUI_USE_OPENGL)
     if (m_uses_point_size)
         CHK(glEnable(GL_PROGRAM_POINT_SIZE));
+#endif
 }
 
 void Shader::end() {
     if (m_blend_mode == BlendMode::AlphaBlend)
         CHK(glDisable(GL_BLEND));
+#if defined(NANOGUI_USE_OPENGL)
     if (m_uses_point_size)
         CHK(glDisable(GL_PROGRAM_POINT_SIZE));
-#if defined(NANOGUI_USE_OPENGL)
     CHK(glBindVertexArray(0));
 #else
     for (const auto &[key, buf] : m_buffers) {

src/texture_gl.cpp

@@ -156,14 +156,16 @@ void Texture::upload(const uint8_t *data) {
         GLenum tex_mode = m_samples > 1 ? GL_TEXTURE_2D_MULTISAMPLE : GL_TEXTURE_2D;
         CHK(glBindTexture(tex_mode, m_texture_handle));
 
-        if (data) {
+        if (data)
             CHK(glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
+
+#if defined(NANOGUI_USE_OPENGL)
+        if (data) {
             CHK(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
             CHK(glPixelStorei(GL_UNPACK_SKIP_ROWS, 0));
             CHK(glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0));
         }
 
-#if defined(NANOGUI_USE_OPENGL)
         if (m_samples == 1)
             CHK(glTexImage2D(tex_mode, 0, internal_format_gl, (GLsizei) m_size.x(),
                              (GLsizei) m_size.y(), 0, pixel_format_gl, component_format_gl, data));