gtkseisviewgl.c

segy 显示程序！希望能给正在做这部分朋友提供一部分资料

                tex_coord_bottom = j != (private->tex_fast_num - 1) ? 1.0 - tex_coord_offset : 1.0;

                glBindTexture (GL_TEXTURE_2D, private->tex_id[i * private->tex_fast_num + j]);

                glBegin (GL_QUADS);

                glTexCoord2d (tex_coord_top, tex_coord_left);
                glVertex2d (tex_vertex_left, tex_vertex_top);

                glTexCoord2d (tex_coord_top, tex_coord_right);
                glVertex2d (tex_vertex_right, tex_vertex_top);

                glTexCoord2d (tex_coord_bottom, tex_coord_right);
                glVertex2d (tex_vertex_right, tex_vertex_bottom);

                glTexCoord2d (tex_coord_bottom, tex_coord_left);
                glVertex2d (tex_vertex_left, tex_vertex_bottom);

                glEnd ();
            }
        }
        glBindTexture (GL_TEXTURE_2D, 0);
        glDisable (GL_TEXTURE_2D);
        if (GTK_SEIS_VIEW_TEX_PALETTED == private->tex_color_mode)
            glDisable (GL_SHARED_TEXTURE_PALETTE_EXT);
        else if (GTK_SEIS_VIEW_TEX_FRAG_COLOR == private->tex_color_mode) {
            private->shaders->glUseProgramObjectARB (0);
            private->gl13->glActiveTexture (GL_TEXTURE1);
            glBindTexture (GL_TEXTURE_1D, 0);
            glDisable (GL_TEXTURE_1D);
            private->gl13->glActiveTexture (GL_TEXTURE0);
        }
    } else {
        /* Simply put a one-color rectangle underneath the traces if the variable density mode is disabled */
        glBegin (GL_QUADS);
        glVertex2f (private->data_vis.slow_start_object, private->data_vis.fast_start_object);
        glVertex2f (private->data_vis.slow_start_object + private->data_vis.slow_size_object, private->data_vis.fast_start_object);
        glVertex2f (private->data_vis.slow_start_object + private->data_vis.slow_size_object, private->data_vis.fast_start_object + private->data_vis.fast_size_object);
        glVertex2f (private->data_vis.slow_start_object, private->data_vis.fast_start_object + private->data_vis.fast_size_object);
        glEnd ();
    }

    /* Distance between traces in the object space */
    gfloat trace_dist = slow_data_to_object_scale / (gfloat)(private->slow_num);
    /* Start locations of the first trace */
    gfloat trace_slow_start = tex_slow_start + trace_dist / 2.0;
    gfloat trace_fast_start = tex_fast_start;
    GLuint va_list_base = private->va_fill_mode == GTK_SEIS_VIEW_VA_POSITIVE ? private->va_list_pos_base
                                                                             : private->va_list_neg_base;
    GLuint *traces_va_vbo = private->va_fill_mode == GTK_SEIS_VIEW_VA_POSITIVE ? private->traces_va_pos_vbo
                                                                               : private->traces_va_neg_vbo;
    GLsizei *va_index_num = private->va_fill_mode == GTK_SEIS_VIEW_VA_POSITIVE ? private->va_pos_num
                                                                               : private->va_neg_num;

    GLdouble win_x, win_y, win_z;
    GLdouble obj_x1, obj_x2, obj_y, obj_z;
    GLdouble min_trace_dist;
    guint trace_step_index = 1, trace_start_index = 0, trace_end_index = 0;

    win_z = 0;

    /* We are going to calculate a distance in the object space corresponding to
       a distance of 3 pixels in the screen space. We need it to calculate the
       minimum allowable distance between traces in the object space */
    win_x = private->data_vis.slow_start_screen;
    win_y = GTK_WIDGET (self)->allocation.height  - private->data_vis.fast_start_screen;
    gluUnProject (win_x, win_y, win_z, private->data_vis.model_view, private->data_vis.projection, private->data_vis.viewport,
                  &obj_x1, &obj_y, &obj_z);
    win_x += 3;
    gluUnProject (win_x, win_y, win_z, private->data_vis.model_view, private->data_vis.projection, private->data_vis.viewport,
                  &obj_x2, &obj_y, &obj_z);
    min_trace_dist = obj_x2 - obj_x1;
    /* Trace increment according to the minimum allowable distance */
    trace_step_index = min_trace_dist / trace_dist + 0.5;
    while (trace_dist * trace_step_index < min_trace_dist)
        trace_step_index += 1;

    /* Indices of the first and the last traces we are going to render */
    trace_start_index = (private->data_vis.slow_start_object - trace_slow_start - trace_dist * private->trace_scale) / trace_dist;
    trace_end_index = (private->data_vis.slow_start_object + private->data_vis.slow_size_object - trace_slow_start +
                                                             trace_dist * private->trace_scale) / trace_dist;

    if (trace_start_index > private->slow_num)
        trace_start_index = 0;

    if (trace_end_index >= private->slow_num)
        trace_end_index = private->slow_num - 1;

    if (trace_step_index == private->last_trace_step_index) {
        while (((abs ((gint)trace_start_index - (gint)private->last_trace_start_index)) % trace_step_index) &&
               trace_start_index != 0)
            trace_start_index -= 1;
    } else
        private->last_trace_step_index = trace_step_index;

    private->last_trace_start_index = trace_start_index;

    guint trace_hlight_start_index = private->slow_num, trace_hlight_end_index = private->slow_num;
    if (private->hlight_start_data >= 0 && private->hlight_size_data >= 0) {
        trace_hlight_start_index = private->hlight_start_data * slow_data_to_object_scale / trace_dist;
        trace_hlight_end_index = trace_hlight_start_index + private->hlight_size_data * slow_data_to_object_scale / trace_dist;

        trace_hlight_start_index = (gint)(trace_hlight_start_index / trace_step_index + 1.0) * trace_step_index - 0.5;
        trace_hlight_end_index = (gint)(trace_hlight_end_index / trace_step_index + 1.0) * trace_step_index - 0.5;

        if (trace_hlight_end_index < trace_start_index ||
            trace_hlight_start_index > trace_end_index) {
            trace_hlight_start_index = private->slow_num;
            trace_hlight_end_index = private->slow_num;
        } else if (trace_hlight_start_index < trace_start_index)
            trace_hlight_start_index = trace_start_index;
        else if (trace_hlight_end_index > trace_end_index)
            trace_hlight_end_index = trace_end_index;

        if (trace_hlight_end_index < trace_hlight_start_index)
            trace_hlight_end_index = trace_hlight_start_index;
    }

/*
#ifdef DEBUG
    g_printf ("Rendering traces from number %u to number %u with step %u\n", trace_start_index,
                                                                             trace_end_index,
                                                                             trace_step_index);
#endif*/

    gfloat trace_scale = private->trace_scale;

    if (private->inverse_polarity) {
        trace_scale = -trace_scale;
        glFrontFace (GL_CCW);
    }

    glColor3f (private->trace_color.red / (gfloat)G_MAXUINT16,
               private->trace_color.green / (gfloat)G_MAXUINT16,
               private->trace_color.blue / (gfloat)G_MAXUINT16);

    if (private->vbo && private->has_wiggles) { /* VBOs */
        glEnableClientState (GL_VERTEX_ARRAY);
        glEnableClientState (GL_INDEX_ARRAY);

        if ((private->display_mode & (GTK_SEIS_VIEW_VA | GTK_SEIS_VIEW_WIGGLE)) ==
            (GTK_SEIS_VIEW_VA | GTK_SEIS_VIEW_WIGGLE) ||
            (trace_hlight_start_index < private->slow_num &&
             GTK_SEIS_VIEW_VD == private->display_mode)) {
            /* Wiggle + variable area */
            if (private->display_mode != GTK_SEIS_VIEW_VD) {
                for (i = trace_start_index; i <= trace_end_index; i += trace_step_index) {
                    if (i >= trace_hlight_start_index && i <= trace_hlight_end_index)
                        continue;
                    glPushMatrix ();
                    glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                    glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                              fast_data_to_object_scale, 0);
                    private->vbo->glBindBufferARB (GL_ARRAY_BUFFER_ARB, private->traces_wiggle_vbo[i]);
                    glVertexPointer (2, GL_FLOAT, 0, NULL);
                    glDrawArrays (GL_LINE_STRIP, 0, private->wiggle_num[i]);
                    private->vbo->glBindBufferARB (GL_ELEMENT_ARRAY_BUFFER_ARB, traces_va_vbo[i]);
                    glIndexPointer (GL_INT, 0, NULL);
                    glDrawElements (GL_TRIANGLE_STRIP, va_index_num[i], GL_UNSIGNED_INT, NULL);
                    glPopMatrix ();
                }
            }
            /* Highlight */
            if (trace_hlight_start_index < private->slow_num && trace_hlight_start_index < private->slow_num) {
                glColor3f (private->highlight_color.red / (gfloat)G_MAXUINT16,
                           private->highlight_color.green / (gfloat)G_MAXUINT16,
                           private->highlight_color.blue / (gfloat)G_MAXUINT16);
                for (i = trace_hlight_start_index; i <= trace_hlight_end_index; i += trace_step_index) {
                    glPushMatrix ();
                    glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                    glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                              fast_data_to_object_scale, 0);
                    private->vbo->glBindBufferARB (GL_ARRAY_BUFFER_ARB, private->traces_wiggle_vbo[i]);
                    glVertexPointer (2, GL_FLOAT, 0, NULL);
                    glDrawArrays (GL_LINE_STRIP, 0, private->wiggle_num[i]);
                    private->vbo->glBindBufferARB (GL_ELEMENT_ARRAY_BUFFER_ARB, traces_va_vbo[i]);
                    glIndexPointer (GL_INT, 0, NULL);
                    glDrawElements (GL_TRIANGLE_STRIP, va_index_num[i], GL_UNSIGNED_INT, NULL);
                    glPopMatrix ();
                }
            }
        } else if (private->display_mode & GTK_SEIS_VIEW_VA) {
            /* Only variable area */
            for (i = trace_start_index; i <= trace_end_index; i += trace_step_index) {
                if (i >= trace_hlight_start_index && i <= trace_hlight_end_index)
                    continue;
                glPushMatrix ();
                glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                          fast_data_to_object_scale, 0);
                private->vbo->glBindBufferARB (GL_ARRAY_BUFFER_ARB, private->traces_wiggle_vbo[i]);
                glVertexPointer (2, GL_FLOAT, 0, NULL);
                private->vbo->glBindBufferARB (GL_ELEMENT_ARRAY_BUFFER_ARB, traces_va_vbo[i]);
                glIndexPointer (GL_INT, 0, NULL);
                glDrawElements (GL_TRIANGLE_STRIP, va_index_num[i], GL_UNSIGNED_INT, NULL);
                glPopMatrix ();
            }
            /* Highlight */
            if (trace_hlight_start_index < private->slow_num && trace_hlight_start_index < private->slow_num) {
                glColor3f (private->highlight_color.red / (gfloat)G_MAXUINT16,
                           private->highlight_color.green / (gfloat)G_MAXUINT16,
                           private->highlight_color.blue / (gfloat)G_MAXUINT16);
                for (i = trace_hlight_start_index; i <= trace_hlight_end_index; i += trace_step_index) {
                    glPushMatrix ();
                    glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                    glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                              fast_data_to_object_scale, 0);
                    private->vbo->glBindBufferARB (GL_ARRAY_BUFFER_ARB, private->traces_wiggle_vbo[i]);
                    glVertexPointer (2, GL_FLOAT, 0, NULL);
                    private->vbo->glBindBufferARB (GL_ELEMENT_ARRAY_BUFFER_ARB, traces_va_vbo[i]);
                    glIndexPointer (GL_INT, 0, NULL);
                    glDrawElements (GL_TRIANGLE_STRIP, va_index_num[i], GL_UNSIGNED_INT, NULL);
                    glPopMatrix ();
                }
            }
        } else if (private->display_mode & GTK_SEIS_VIEW_WIGGLE) {
            /* Only wiggle */
            for (i = trace_start_index; i <= trace_end_index; i += trace_step_index) {
                if (i >= trace_hlight_start_index && i <= trace_hlight_end_index)
                    continue;
                glPushMatrix ();
                glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                          fast_data_to_object_scale, 0);
                private->vbo->glBindBufferARB (GL_ARRAY_BUFFER_ARB, private->traces_wiggle_vbo[i]);
                glVertexPointer (2, GL_FLOAT, 0, NULL);
                glDrawArrays (GL_LINE_STRIP, 0, private->wiggle_num[i]);
                glPopMatrix ();
            }
            /* Highlight */
            if (trace_hlight_start_index < private->slow_num && trace_hlight_start_index < private->slow_num) {
                glColor3f (private->highlight_color.red / (gfloat)G_MAXUINT16,
                           private->highlight_color.green / (gfloat)G_MAXUINT16,
                           private->highlight_color.blue / (gfloat)G_MAXUINT16);
                for (i = trace_hlight_start_index; i <= trace_hlight_end_index; i += trace_step_index) {
                    glPushMatrix ();
                    glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                    glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                              fast_data_to_object_scale, 0);
                    private->vbo->glBindBufferARB (GL_ARRAY_BUFFER_ARB, private->traces_wiggle_vbo[i]);
                    glVertexPointer (2, GL_FLOAT, 0, NULL);
                    glDrawArrays (GL_LINE_STRIP, 0, private->wiggle_num[i]);
                    glPopMatrix ();
                }
            }
        }
        glDisableClientState (GL_INDEX_ARRAY);
        glDisableClientState (GL_VERTEX_ARRAY);
     } else if (private->has_wiggles) { /* Display lists */
        if ((private->display_mode & (GTK_SEIS_VIEW_VA | GTK_SEIS_VIEW_WIGGLE)) ==
            (GTK_SEIS_VIEW_VA | GTK_SEIS_VIEW_WIGGLE) ||
            (trace_hlight_start_index < private->slow_num &&
             GTK_SEIS_VIEW_VD == private->display_mode)) {
            /* Wiggle + variable area */
            if (private->display_mode != GTK_SEIS_VIEW_VD) {
                for (i = trace_start_index; i <= trace_end_index; i += trace_step_index) {
                    if (i >= trace_hlight_start_index && i <= trace_hlight_end_index)
                        continue;
                    glPushMatrix ();
                    glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                    glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                              fast_data_to_object_scale, 0);
                    glCallList (private->wiggle_list_base + i);
                    glCallList (va_list_base + i);
                    glPopMatrix ();
                }
            }
            /* Highlight */
            if (trace_hlight_start_index < private->slow_num && trace_hlight_start_index < private->slow_num) {
                glColor3f (private->highlight_color.red / (gfloat)G_MAXUINT16,
                           private->highlight_color.green / (gfloat)G_MAXUINT16,
                           private->highlight_color.blue / (gfloat)G_MAXUINT16);
                for (i = trace_hlight_start_index; i <= trace_hlight_end_index; i += trace_step_index) {
                    glPushMatrix ();
                    glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                    glScalef (slow_data_to_object_scale * trace_scale * trace_step_index, 
                              fast_data_to_object_scale, 0);
                    glCallList (private->wiggle_list_base + i);
                    glCallList (va_list_base + i);
                    glPopMatrix ();
                }
            }
        } else if (private->display_mode & GTK_SEIS_VIEW_VA) {
            /* Only variable area */
            for (i = trace_start_index; i <= trace_end_index; i += trace_step_index) {
                if (i >= trace_hlight_start_index && i <= trace_hlight_end_index)
                    continue;
                glPushMatrix ();
                glTranslatef (trace_slow_start + trace_dist * i, trace_fast_start, 0);
                glScalef (slow_data_to_object_scale * trace_scale * trace_step_index,
                          fast_data_to_object_scale, 0);
                glCallList (va_list_base + i);
                glPopMatrix ();
            }
            /* Highlight */
            if (trace_hlight_start_index < private->slow_num && trace_hlight_start_index < pri