Make the initializing functions also drop fixed function usage.
[movit] / init.cpp
index b8b3cb4..4003163 100644 (file)
--- a/init.cpp
+++ b/init.cpp
@@ -1,23 +1,34 @@
 #include <GL/glew.h>
+#include <assert.h>
+#include <stddef.h>
+#include <algorithm>
 #include <string>
 
 #include "init.h"
+#include "resource_pool.h"
 #include "util.h"
 
+using namespace std;
+
+namespace movit {
+
 bool movit_initialized = false;
 MovitDebugLevel movit_debug_level = MOVIT_DEBUG_ON;
 float movit_texel_subpixel_precision;
 bool movit_srgb_textures_supported;
+int movit_num_wrongly_rounded;
+bool movit_shader_rounding_supported;
 
 // The rules for objects with nontrivial constructors in static scope
 // are somewhat convoluted, and easy to mess up. We simply have a
 // pointer instead (and never care to clean it up).
-std::string *movit_data_directory = NULL;
+string *movit_data_directory = NULL;
 
 namespace {
 
 void measure_texel_subpixel_precision()
 {
+       ResourcePool resource_pool;
        static const unsigned width = 4096;
 
        // Generate a destination texture to render to, and an FBO.
@@ -45,9 +56,9 @@ void measure_texel_subpixel_precision()
        // Now generate a simple texture that's just [0,1].
        GLuint src_texnum;
        float texdata[] = { 0, 1 };
-       glGenTextures(1, &dst_texnum);
+       glGenTextures(1, &src_texnum);
        check_error();
-       glBindTexture(GL_TEXTURE_1D, dst_texnum);
+       glBindTexture(GL_TEXTURE_1D, src_texnum);
        check_error();
        glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        check_error();
@@ -55,8 +66,6 @@ void measure_texel_subpixel_precision()
        check_error();
        glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE16F_ARB, 2, 0, GL_LUMINANCE, GL_FLOAT, texdata);
        check_error();
-       glEnable(GL_TEXTURE_1D);
-       check_error();
 
        // Basic state.
        glDisable(GL_BLEND);
@@ -68,36 +77,51 @@ void measure_texel_subpixel_precision()
 
        glViewport(0, 0, width, 1);
 
-       glMatrixMode(GL_PROJECTION);
-       glLoadIdentity();
-       glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
-
-       glMatrixMode(GL_MODELVIEW);
-       glLoadIdentity();
+       GLuint glsl_program_num = resource_pool.compile_glsl_program(
+               read_file("vs.vert"), read_file("texture1d.frag"));
+       glUseProgram(glsl_program_num);
+       check_error();
+       glUniform1i(glGetUniformLocation(glsl_program_num, "tex"), 0);  // Bind the 1D sampler.
        check_error();
 
        // Draw the texture stretched over a long quad, interpolating it out.
        // Note that since the texel center is in (0.5), we need to adjust the
        // texture coordinates in order not to get long stretches of (1,1,1,...)
        // at the start and (...,0,0,0) at the end.
-       glBegin(GL_QUADS);
-
-       glTexCoord1f(0.25f);
-       glVertex2f(0.0f, 0.0f);
-
-       glTexCoord1f(0.75f);
-       glVertex2f(1.0f, 0.0f);
-
-       glTexCoord1f(0.75f);
-       glVertex2f(1.0f, 1.0f);
-
-       glTexCoord1f(0.25f);
-       glVertex2f(0.0f, 1.0f);
+       float vertices[] = {
+               0.0f, 0.0f,
+               1.0f, 0.0f,
+               1.0f, 1.0f,
+               0.0f, 1.0f
+       };
+       float texcoords[] = {
+               0.25f, 0.0f,
+               0.75f, 0.0f,
+               0.75f, 0.0f,
+               0.25f, 0.0f
+       };
+
+       int position_attrib = glGetAttribLocation(glsl_program_num, "position");
+       assert(position_attrib != -1);
+       int texcoord_attrib = glGetAttribLocation(glsl_program_num, "texcoord");
+       assert(texcoord_attrib != -1);
+       glEnableVertexAttribArray(position_attrib);
+       check_error();
+       glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, vertices);
+       check_error();
+       glEnableVertexAttribArray(texcoord_attrib);
+       check_error();
+       glVertexAttribPointer(texcoord_attrib, 2, GL_FLOAT, GL_FALSE, 0, texcoords);
+       check_error();
 
-       glEnd();
+       glDrawArrays(GL_QUADS, 0, 4);
        check_error();
 
-       glDisable(GL_TEXTURE_1D);
+       glUseProgram(0);
+       check_error();
+       glDisableVertexAttribArray(position_attrib);
+       check_error();
+       glDisableVertexAttribArray(texcoord_attrib);
        check_error();
 
        // Now read the data back and see what the card did.
@@ -110,9 +134,10 @@ void measure_texel_subpixel_precision()
        float biggest_jump = 0.0f;
        for (unsigned i = 1; i < width; ++i) {
                assert(out_data[i] >= out_data[i - 1]);
-               biggest_jump = std::max(biggest_jump, out_data[i] - out_data[i - 1]);
+               biggest_jump = max(biggest_jump, out_data[i] - out_data[i - 1]);
        }
 
+       assert(biggest_jump > 0.0);
        movit_texel_subpixel_precision = biggest_jump;
 
        // Clean up.
@@ -126,52 +151,200 @@ void measure_texel_subpixel_precision()
        check_error();
        glDeleteTextures(1, &src_texnum);
        check_error();
+
+       resource_pool.release_glsl_program(glsl_program_num);
 }
 
-void check_extensions()
+void measure_roundoff_problems()
+{
+       ResourcePool resource_pool;
+
+       // Generate a destination texture to render to, and an FBO.
+       GLuint dst_texnum, fbo;
+
+       glGenTextures(1, &dst_texnum);
+       check_error();
+       glBindTexture(GL_TEXTURE_2D, dst_texnum);
+       check_error();
+       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 512, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+       check_error();
+
+       glGenFramebuffers(1, &fbo);
+       check_error();
+       glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+       check_error();
+       glFramebufferTexture2D(
+               GL_FRAMEBUFFER,
+               GL_COLOR_ATTACHMENT0,
+               GL_TEXTURE_2D,
+               dst_texnum,
+               0);
+       check_error();
+
+       // Now generate a texture where every value except the last should be
+       // rounded up to the next one. However, there are cards (in highly
+       // common use) that can't do this right, for unknown reasons.
+       GLuint src_texnum;
+       float texdata[512];
+       for (int i = 0; i < 256; ++i) {
+               texdata[i * 2 + 0] = (i + 0.48) / 255.0;
+               texdata[i * 2 + 1] = (i + 0.52) / 255.0;
+       }
+       glGenTextures(1, &src_texnum);
+       check_error();
+       glBindTexture(GL_TEXTURE_1D, src_texnum);
+       check_error();
+       glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+       check_error();
+       glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+       check_error();
+       glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE32F_ARB, 512, 0, GL_LUMINANCE, GL_FLOAT, texdata);
+       check_error();
+
+       // Basic state.
+       glDisable(GL_BLEND);
+       check_error();
+       glDisable(GL_DEPTH_TEST);
+       check_error();
+       glDepthMask(GL_FALSE);
+       check_error();
+
+       glViewport(0, 0, 512, 1);
+
+       GLuint glsl_program_num = resource_pool.compile_glsl_program(
+               read_file("vs.vert"), read_file("texture1d.frag"));
+       glUseProgram(glsl_program_num);
+       check_error();
+       glUniform1i(glGetUniformLocation(glsl_program_num, "tex"), 0);  // Bind the 1D sampler.
+
+       // Draw the texture stretched over a long quad, interpolating it out.
+       float vertices[] = {
+               0.0f, 0.0f,
+               1.0f, 0.0f,
+               1.0f, 1.0f,
+               0.0f, 1.0f
+       };
+       float texcoords[] = {
+               0.25f, 0.0f,
+               0.75f, 0.0f,
+               0.75f, 0.0f,
+               0.25f, 0.0f
+       };
+       int position_attrib = glGetAttribLocation(glsl_program_num, "position");
+       assert(position_attrib != -1);
+       int texcoord_attrib = glGetAttribLocation(glsl_program_num, "texcoord");
+       assert(texcoord_attrib != -1);
+       glEnableVertexAttribArray(position_attrib);
+       check_error();
+       glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, vertices);
+       check_error();
+       glEnableVertexAttribArray(texcoord_attrib);
+       check_error();
+       glVertexAttribPointer(texcoord_attrib, 2, GL_FLOAT, GL_FALSE, 0, texcoords);
+       check_error();
+       glDrawArrays(GL_QUADS, 0, 4);
+
+       glUseProgram(0);
+       check_error();
+       glDisableVertexAttribArray(position_attrib);
+       check_error();
+       glDisableVertexAttribArray(texcoord_attrib);
+
+       // 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];
+       glReadPixels(0, 0, 512, 1, GL_RED, GL_UNSIGNED_BYTE, out_data);
+       check_error();
+
+       int wrongly_rounded = 0;
+       for (unsigned i = 0; i < 255; ++i) {
+               if (out_data[i * 2 + 0] != i) {
+                       ++wrongly_rounded;
+               }
+               if (out_data[i * 2 + 1] != i + 1) {
+                       ++wrongly_rounded;
+               }
+       }
+
+       movit_num_wrongly_rounded = wrongly_rounded;
+
+       // Clean up.
+       glBindTexture(GL_TEXTURE_1D, 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);
+}
+
+bool check_extensions()
 {
        // We fundamentally need FBOs and floating-point textures.
-       assert(glewIsSupported("GL_ARB_framebuffer_object") != 0);
-       assert(glewIsSupported("GL_ARB_texture_float") != 0);
+       if (!glewIsSupported("GL_ARB_framebuffer_object")) return false;
+       if (!glewIsSupported("GL_ARB_texture_float")) return false;
 
        // We assume that we can use non-power-of-two textures without restrictions.
-       assert(glewIsSupported("GL_ARB_texture_non_power_of_two") != 0);
+       if (!glewIsSupported("GL_ARB_texture_non_power_of_two")) return false;
 
        // We also need GLSL fragment shaders.
-       assert(glewIsSupported("GL_ARB_fragment_shader") != 0);
-       assert(glewIsSupported("GL_ARB_shading_language_100") != 0);
+       if (!glewIsSupported("GL_ARB_fragment_shader")) return false;
+       if (!glewIsSupported("GL_ARB_shading_language_100")) return false;
 
        // FlatInput and YCbCrInput uses PBOs. (They could in theory do without,
        // but no modern card would really not provide it.)
-       assert(glewIsSupported("GL_ARB_pixel_buffer_object") != 0);
+       if (!glewIsSupported("GL_ARB_pixel_buffer_object")) return false;
 
        // ResampleEffect uses RG textures to encode a two-component LUT.
-       assert(glewIsSupported("GL_ARB_texture_rg") != 0);
+       if (!glewIsSupported("GL_ARB_texture_rg")) return false;
 
        // sRGB texture decode would be nice, but are not mandatory
        // (GammaExpansionEffect can do the same thing if needed).
        movit_srgb_textures_supported = glewIsSupported("GL_EXT_texture_sRGB");
+
+       // We may want to use round() at the end of the final shader,
+       // if supported. We need either GLSL 1.30 or this extension to do that,
+       // and 1.30 brings with it other things that we don't want to demand
+       // for now.
+       movit_shader_rounding_supported = glewIsSupported("GL_EXT_gpu_shader4");
+
+       return true;
 }
 
 }  // namespace
 
-void init_movit(const std::string& data_directory, MovitDebugLevel debug_level)
+bool init_movit(const string& data_directory, MovitDebugLevel debug_level)
 {
        if (movit_initialized) {
-               return;
+               return true;
        }
 
-       movit_data_directory = new std::string(data_directory);
+       movit_data_directory = new string(data_directory);
        movit_debug_level = debug_level;
 
-       glewInit();
+       GLenum err = glewInit();
+       if (err != GLEW_OK) {
+               return false;
+       }
 
        // geez 
        glPixelStorei(GL_PACK_ALIGNMENT, 1);
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+       glDisable(GL_DITHER);
 
+       if (!check_extensions()) {
+               return false;
+       }
        measure_texel_subpixel_precision();
-       check_extensions();
+       measure_roundoff_problems();
 
        movit_initialized = true;
+       return true;
 }
+
+}  // namespace movit