+ // Basic state.
+ glDisable(GL_BLEND);
+ check_error();
+ glDisable(GL_DEPTH_TEST);
+ check_error();
+ glDepthMask(GL_FALSE);
+ check_error();
+
+ glViewport(0, 0, 512, 1);
+
+ vector<string> frag_shader_outputs;
+ GLuint glsl_program_num = resource_pool.compile_glsl_program(
+ read_version_dependent_file("vs", "vert"),
+ read_version_dependent_file("texture1d", "frag"),
+ frag_shader_outputs);
+ glUseProgram(glsl_program_num);
+ check_error();
+ glUniform1i(glGetUniformLocation(glsl_program_num, "tex"), 0); // Bind the 2D sampler.
+
+ // Draw the texture stretched over a long quad, interpolating it out.
+ float vertices[] = {
+ 0.0f, 1.0f,
+ 0.0f, 0.0f,
+ 1.0f, 1.0f,
+ 1.0f, 0.0f
+ };
+
+ GLuint vao;
+ glGenVertexArrays(1, &vao);
+ check_error();
+ glBindVertexArray(vao);
+ check_error();
+
+ GLuint position_vbo = fill_vertex_attribute(glsl_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
+ GLuint texcoord_vbo = fill_vertex_attribute(glsl_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices); // Same data.
+
+ glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+ check_error();
+
+ cleanup_vertex_attribute(glsl_program_num, "position", position_vbo);
+ cleanup_vertex_attribute(glsl_program_num, "texcoord", texcoord_vbo);
+
+ glUseProgram(0);
+ check_error();
+
+ // Now read the data back and see what the card did. (Ignore the last value.)
+ // (We only look at the red channel; the others will surely be the same.)
+ unsigned char out_data[512 * 4];
+ glReadPixels(0, 0, 512, 1, GL_RGBA, GL_UNSIGNED_BYTE, out_data);
+ check_error();
+
+ int wrongly_rounded = 0;
+ for (unsigned i = 0; i < 255; ++i) {
+ if (out_data[(i * 2 + 0) * 4] != i) {
+ ++wrongly_rounded;
+ }
+ if (out_data[(i * 2 + 1) * 4] != i + 1) {
+ ++wrongly_rounded;
+ }
+ }
+
+ movit_num_wrongly_rounded = wrongly_rounded;
+
+ // Clean up.
+ glBindTexture(GL_TEXTURE_2D, 0);
+ check_error();
+ glBindFramebuffer(GL_FRAMEBUFFER, 0);
+ check_error();
+ glDeleteFramebuffers(1, &fbo);
+ check_error();
+ glDeleteTextures(1, &dst_texnum);
+ check_error();
+ glDeleteTextures(1, &src_texnum);
+ check_error();
+
+ resource_pool.release_glsl_program(glsl_program_num);
+ glDeleteVertexArrays(1, &vao);
+ check_error();
+}
+
+bool check_extensions()
+{
+ // GLES generally doesn't use extensions as actively as desktop OpenGL.
+ // For now, we say that for GLES, we require GLES 3, which has everything
+ // we need.
+ if (!epoxy_is_desktop_gl()) {
+ if (epoxy_gl_version() >= 30) {
+ return true;
+ } else {
+ fprintf(stderr, "Movit system requirements: GLES version %.1f is too old (GLES 3.0 needed).\n",
+ 0.1f * epoxy_gl_version());
+ fprintf(stderr, "Movit initialization failed.\n");
+ return false;
+ }
+ }
+
+ if (epoxy_gl_version() < 30) {
+ fprintf(stderr, "Movit system requirements: OpenGL version %.1f is too old (OpenGL 3.0 needed).\n",
+ 0.1f * epoxy_gl_version());
+ fprintf(stderr, "Movit initialization failed.\n");
+ return false;
+ }
+
+ // The user can specify that they want a timing report for each
+ // phase in an effect chain. However, that depends on this extension;
+ // without it, we do cannot even create the query objects.
+ movit_timer_queries_supported =
+ (epoxy_gl_version() >= 33 || epoxy_has_gl_extension("GL_ARB_timer_query"));
+
+ // Certain effects have compute shader implementations, which may be
+ // more efficient than the normal fragment shader versions.
+ // GLSL 3.10 supposedly also has compute shaders, but I haven't tested them,
+ // so we require desktop OpenGL.
+ movit_compute_shaders_supported =
+ (epoxy_is_desktop_gl() &&
+ (epoxy_gl_version() >= 43 ||
+ (epoxy_has_gl_extension("GL_ARB_compute_shader") &&
+ epoxy_has_gl_extension("GL_ARB_shader_image_load_store"))));
+
+ return true;
+}
+
+double get_glsl_version()
+{
+ char *glsl_version_str = strdup((const char *)glGetString(GL_SHADING_LANGUAGE_VERSION));
+
+ // Skip past the first period.
+ char *ptr = strchr(glsl_version_str, '.');
+ assert(ptr != nullptr);
+ ++ptr;
+
+ // Now cut the string off at the next period or space, whatever comes first
+ // (unless the string ends first).
+ while (*ptr && *ptr != '.' && *ptr != ' ') {
+ ++ptr;
+ }
+ *ptr = '\0';
+
+ // Now we have something on the form X.YY. We convert it to a float, and hope
+ // that if it's inexact (e.g. 1.30), atof() will round the same way the
+ // compiler will.
+ std::istringstream locale_convert(glsl_version_str);
+ locale_convert.imbue(std::locale("C"));
+ double glsl_version;
+ locale_convert >> glsl_version;
+ free(glsl_version_str);
+
+ return glsl_version;
+}
+
+void APIENTRY debug_callback(GLenum source,
+ GLenum type,
+ GLuint id,
+ GLenum severity,
+ GLsizei length,
+ const char *message,
+ const void *userParam)
+#ifdef __GNUC__
+ __attribute__((unused))
+#endif
+;
+
+void APIENTRY debug_callback(GLenum source,
+ GLenum type,
+ GLuint id,
+ GLenum severity,
+ GLsizei length,
+ const char *message,
+ const void *userParam)
+{
+ printf("Debug: %s\n", message);