Make the initializing functions also drop fixed function usage.
authorSteinar H. Gunderson <sgunderson@bigfoot.com>
Sat, 8 Mar 2014 17:37:25 +0000 (18:37 +0100)
committerSteinar H. Gunderson <sgunderson@bigfoot.com>
Sat, 8 Mar 2014 20:57:27 +0000 (21:57 +0100)
init.cpp
texture1d.frag [new file with mode: 0644]

index 5717dda..4003163 100644 (file)
--- a/init.cpp
+++ b/init.cpp
@@ -5,6 +5,7 @@
 #include <string>
 
 #include "init.h"
+#include "resource_pool.h"
 #include "util.h"
 
 using namespace std;
@@ -27,6 +28,7 @@ namespace {
 
 void measure_texel_subpixel_precision()
 {
+       ResourcePool resource_pool;
        static const unsigned width = 4096;
 
        // Generate a destination texture to render to, and an FBO.
@@ -64,8 +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);
@@ -77,36 +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);
+       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
+       };
 
-       glTexCoord1f(0.75f);
-       glVertex2f(1.0f, 0.0f);
-
-       glTexCoord1f(0.75f);
-       glVertex2f(1.0f, 1.0f);
-
-       glTexCoord1f(0.25f);
-       glVertex2f(0.0f, 1.0f);
+       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.
@@ -122,6 +137,7 @@ void measure_texel_subpixel_precision()
                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.
@@ -135,10 +151,14 @@ void measure_texel_subpixel_precision()
        check_error();
        glDeleteTextures(1, &src_texnum);
        check_error();
+
+       resource_pool.release_glsl_program(glsl_program_num);
 }
 
 void measure_roundoff_problems()
 {
+       ResourcePool resource_pool;
+
        // Generate a destination texture to render to, and an FBO.
        GLuint dst_texnum, fbo;
 
@@ -180,8 +200,6 @@ void measure_roundoff_problems()
        check_error();
        glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE32F_ARB, 512, 0, GL_LUMINANCE, GL_FLOAT, texdata);
        check_error();
-       glEnable(GL_TEXTURE_1D);
-       check_error();
 
        // Basic state.
        glDisable(GL_BLEND);
@@ -193,34 +211,44 @@ void measure_roundoff_problems()
 
        glViewport(0, 0, 512, 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.
 
        // Draw the texture stretched over a long quad, interpolating it out.
-       glBegin(GL_QUADS);
-
-       glTexCoord1f(0.0f);
-       glVertex2f(0.0f, 0.0f);
-
-       glTexCoord1f(1.0f);
-       glVertex2f(1.0f, 0.0f);
-
-       glTexCoord1f(1.0f);
-       glVertex2f(1.0f, 1.0f);
-
-       glTexCoord1f(0.0f);
-       glVertex2f(0.0f, 1.0f);
-
-       glEnd();
+       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);
 
-       glDisable(GL_TEXTURE_1D);
+       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.)
@@ -251,6 +279,8 @@ void measure_roundoff_problems()
        check_error();
        glDeleteTextures(1, &src_texnum);
        check_error();
+
+       resource_pool.release_glsl_program(glsl_program_num);
 }
 
 bool check_extensions()
diff --git a/texture1d.frag b/texture1d.frag
new file mode 100644 (file)
index 0000000..4f8b981
--- /dev/null
@@ -0,0 +1,7 @@
+uniform sampler1D tex;
+varying vec2 tc;
+
+void main()
+{
+       gl_FragColor = texture1D(tex, tc.x);
+}