+ 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();
+ glEnable(GL_TEXTURE_1D);
+ 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);
+
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
+
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+ check_error();
+
+ // 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();
+ check_error();
+
+ glDisable(GL_TEXTURE_1D);
+ 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];
+ 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();